Computers normally have a single operating system installed on them, but you can dual-boot multiple operating systems. You can have two (or more) versions of Windows installed side-by-side on the same PC and choose between them at boot time.

Typically, you should install the newer operating system last. For example, if you want to dual-boot Windows 7 and 10, install Windows 7 and then install Windows 10 second. However, this may not always be necessary — installing Windows 7 after Windows 8 or 8.1 seems to work.

The Basics
The process for creating a dual-boot system is similar no matter what operating system you’re dual-booting with. Here’s what you’ll need to do:

Install the First Version of Windows: If you already have a single Windows system installed on your computer, that’s fine. If not, install Windows normally. You may want to use custom partitioning settings and leave free space available on your hard drive for the second version of Windows.
Make Room For the Second Version of Windows: You’ll need available hard drive space for the next version of Windows. If you have Windows installed, you can resize the partition. You could also insert a second hard drive into your computer (if it’s a desktop computer) and install the second version of Windows to that hard drive.
Install the Second Version of Windows: Next, you’ll install the second version of Windows. Ensure you choose the “Custom Install” option, not the “Upgrade” option. Install it alongside the previous version of Windows, in a different partition on the same disk or on a different physical disk.
You’ll then be able to choose which copy of Windows you want to boot at boot time, and you can access the files from each version of Windows on the other one.

Install the First Version of Windows, If It’s Not Already Installed
Install the first version of Windows on your PC, assuming it’s not already installed. If your computer already has Windows installed on it, that’s fine. If you’re installing Windows fresh, you’ll want to choose the “Custom install” option when going through the installation wizard and create a smaller partition for Windows. Leave enough space for the other version of Windows. This means you won’t have to resize partitions later.



Shrink Your Windows Partition
You’ll now need to shrink your existing Windows partition to make room for the second copy of Windows. If you already have enough free space or you’re installing the second copy of Windows to a different hard disk entirely and it has available space, you can skip this.

Basically, this involves booting the existing Windows system on your computer and opening the Disk Management tool. (Do this by pressing Windows Key + R, typing diskmgmt.msc into the Run dialog, and pressing Enter.) Right-click the Windows partition and select the “Shrink Volume” option. Shrink it to make enough space for the other Windows system.

RELATED: How to Set Up BitLocker Encryption on Windows

If you’re using BitLocker encryption on your Windows system, you’ll first need to open the BitLocker Control Panel and click the “Suspend Protection” link next to the partition you want to resize. This will disable BitLocker encrpytion until you next reboot, and you’ll be able to resize the partition. Otherwise, you won’t be able to resize the partition.



Install the Second Version of Windows


Next, insert the installation media for the second version of Windows you want to install and reboot your computer. Boot it and go through the installer normally. When you see the “Upgrade” or “Custom install” option, be sure to select “Custom” — if you select Upgrade, the second version of Windows will install over top of your first version of Windows.



Select the “unallocated space” and create a new partition on it. Tell Windows to install itself to this new partition.  Just be sure not to select the partition containing the version of Windows currently installed on your system, as two versions of Windows can’t be installed on the same partition.

Windows will install normally, but it’ll install alongside the current version of Windows on your PC. Each version of Windows will be on a separate partition.



Choosing Your OS and Modifying Boot Settings
When the installation is finished, you’ll see a boot menu every time you boot your computer. Use this menu to select the version of Windows you want to boot.

Depending on which versions of Windows you’re using, the screen will look different. On Windows 8 and newer versions of Windows, it’s a blue screen with tiles with the title “Choose an operating system.” On Windows 7, it’s a black screen with a list of operating systems and the title “Windows Boot Manager.”



Either way, you can customize the boot menu’s settings from within Windows itself. Open the Control Panel, click the System and Security option, click the System icon, and click Advanced System Settings at the left side of the window. Select the Advanced tab and click the Settings button under Startup & Recovery. You can choose the default operating system that boots automatically and select how long you have until it boots.



If you want more operating systems installed, just install the additional operating systems on their own separate partitions.

While the smartphone has made many of our work easier, there is also a concern about security. Where, when a hacker breaks into our smartphone and stole our most important information, this fear remains often. To overcome this, the scientists continue to develop a better security system. Many smartphones include facial recognition, fingerprint scans and other biometric systems. However, the trouble with these easy-to-use tools is that once compromised they cannot be reset.

But now, American scientists have developed a security system that will use the smartphone's password as the brain of the user after it's been in the market. Smartphones will be unlocked only by recognizing the brainwaves in response to a series of pictures - an advance that could better protect devices from hackers. According to the scientists at Buffalo University, electroencephalography (EEG) is currently a very easy system, through which the waves of the brain can be recorded.

"You can't grow a new fingerprint or iris if that information is divulged," said Wenyao Xu, an assistant professor at the University at Buffalo (UB) in the US. "That's why we're developing a new type of password - one that measures your brainwaves in response to a series of pictures. Like a password, it's easy to reset; and like a biometric, it's easy to use," said Xu.

The "brain password," which presently would require users to wear a headset, but in the future, it has to be tried to make it even better. It could have implications in banking, law enforcement, airport security and other areas.

"To the best of our knowledge, this is the first in-depth research study on a truly cancelable brain biometric system. We refer to this as 'hard cancellation,' meaning the original brain password can be reset without divulging the user's identity," said Zhanpeng Jin, an associate professor at UB.

We have consistently seen various vectors of attack rear their head when it comes to Android smartphones. We’ve seen Shattered Trust, Cloak and Dagger, and Rowhammer, just to name a few. RAMpage is the latest one on the block, and while it is a hardware vulnerability, it doesn’t necessarily need physical access to your device to exploit. How it works is relatively simple.

A group of university researchers have discovered that this vulnerability could theoretically work on any device with LPDDR memory, which includes virtually every smartphone released since 2012, including some Apple devices.

When a CPU reads or writes a row of bits in the RAM module present on the device, the neighbouring rows are slightly affected due to a tiny electric discharge. This isn’t usually a problem as we know RAM does this and that’s why it’s periodically refreshed to make sure nothing goes wrong. But what if we start “hammering” the same “row”? What if we continuously read or write to the same row in order to disrupt neighbouring rows? This can cause a bit-flip in a memory row that we shouldn’t own or have access to at all. That’s what Rowhammer is, and it’s being used as part of a larger vulnerability called RAMpage. The CVE is CVE-2018-9442 and it affects devices shipped with LPDDR2, LPDDR3, or LPDDR4 RAM.

RAMpage can be used to gain root access on a device, but the researchers managed to get it to do a whole lot more as well. It could be used to bypass JavaScript sandboxes and even perform an attack running on another virtual machine on the same computer on x86 devices. ARM-based devices are also vulnerable, and that’s where our Android phones come in. DRAMMER stands for “Deterministic Rowhammer Attacks on Mobile Devices”.

The attack allows a hacker access to the entire operating system. This includes accessing the data stored by other applications, which the Android security model is meant to prevent. An attacker can gain full control of a device allowing them to obtain stored passwords, personal photos, emails, instant messages and even business-critical documents.

If you don’t want to upgrade from an existing Windows installation, you can download the official Windows 10 installation media for free from Microsoft and perform a clean install. To do this, visit Microsoft’s Download Windows 10 page, click “Download Tool Now”, and run the downloaded file. Select “Create installation media for another PC”.

Be sure to select the language, edition, and architecture you want to install of Windows 10. If you’re installing it on a PC with a 64-bit CPU, you probably want the 64-bit version. If you’re installing it on a PC with a 32-bit CPU, you’ll need the 32-bit version. You can check what type of CPU your PC has if you don’t know off the top of your head.

If you’re installing Windows 10 on the current PC, just keep the “Use the recommended options for this PC” box checked and the tool will automatically download the correct version for your current PC.

The tool will allow you to copy the Windows 10 installation files to a USB drive or burn them to a DVD. If you’re using a USB drive, it must be 4 GB or larger in size. All files on the USB drive will be erased as part of this process.

If you want to install Windows 10 in a virtual machine, select the “ISO file” option here. The tool will download an ISO file, and you can then boot the downloaded ISO in a virtual machine to install Windows 10 inside it

Once you’ve created installation media, you’ll need to insert it into the PC you want to install Windows 10 on. You then boot from the installation media. This may require modifying the boot order in your PC’s BIOS or UEFI firmware.

On the Windows Setup screen, select your language, time and currency format, and keyboard layout. Click “Next” to continue.

When you reach the installer screen, select “Install Now” and follow the instructions to install Windows 10 on your PC.

When you see the Activate Windows screen, you’ll need to either enter a key or skip it. You may not see this screen if Windows 10 automatically detects a key associated with your PC’s hardware.

When you reach the “Which type of installation do you want?” screen, click “Custom” to perform a clean installation and remove everything on your PC. (If you’ve changed your mind and want to upgrade your existing installation, you can click “Upgrade”.)

On the next screen, select the hard drive you want to install Windows on and erase it. If you have multiple partitions on that drive, you may want to erase those as well.

Warning: When you delete a partition, you’re also deleting all the files on that partition. Be sure you have backups of any important files before doing this!

When you’re done erasing partitions, you should have a big block of “Unallocated Space”. Select that, click “New”, and once it’s formatted your drive, click Next.

Windows 10 will install itself, and may restart a few times during this process. When it’s done, you’ll see the normal setup interface you see when setting up Windows 10 on any new PC, where you can add user accounts and adjust various settings.

If you already have Windows 10 on your PC and want to perform a fresh install, you can also do that.

Windows 10’s Creators Update makes it much easier to install Windows 10 from scratch. You can use the “Fresh start” option in Windows Defender to get a completely fresh-from-Microsoft Windows 10 system. Unlike the standard Refresh and Reset options, which preserve any bloatware your PC manufacturer installed, this will wipe away all that manufacturer-installed stuff and just leave a fresh Windows 10 system.