When a computer suddenly restarts, the bottom line is that it has a problem which causes it to do this. The way to fix this problem is to repair this problem – and to do that, you need to look through the various issues that often causes it to do this & fix them. The most common reasons why a computer will restart are problem problems, program issues and registry errors. Here's how to fix them:
1) Check For Hardware Problems In "Safe Mode" – The first thing you need to do is to restart your computer in "safe mode". This mode has been created by Microsoft to load up Windows without any of the damaging software / drivers that can cause problems on the typical PC. This means that we can use this mode to test if your computer is restarting thanks to hardware or software problems. The way to do this is to restart your PC and press F8 continuously before it loads. When the "Advanced Boot Options" appears, use the arrow keys to locate "Safe Mode". This will start your computer without any software running, meaning you should use it for a few minutes to see if it restarts. If it restores in safe mode, it suggests you have a hardware problems which should be fixed by a trained professional. However, if it does not restart, you most likely have a problem with the software of your computer.
2) Reinstall Programs Causing The Restart – If your PC restarts when you try and use a specific program (such as Photoshop or a game), then the best thing to do is to completely reinstall that program on your system. To do this, you should open the "Add / Remove Programs" applet inside your PC, and then remove the program causing the issue. After that, reinstall a fresh copy of the program and see if it causes the same problem. Software applications often have a lot of damaged files that they need to run, and if your PC can not read these files, it ends up restarting your system.
3) If The Crashes Are Random, Clean The Registry – The 'registry' is one of the most important parts of Windows, and is also a big cause of problems for your PC as well. This is a database which stores all sorts of settings & information for your computer, allowing you to keep such details as your desktop wallpaper, stored passwords and even your screen resolution safe. The registry is the hidden gem inside Windows, which allows your PC to remember so many different settings every time it loads. This database is the most important part of the Windows system, but is also the reason why your computer often crashes randomly.
The problem is that each time you use Windows, it needs to read 100's of files from the registry to help it run. However, many of these files are difficult to read, or unreadable, making Windows struggle to recall the settings it needs. This is a big problem, and if your PC can not read the settings it needs – it will just restart & crash. This is the most likely reason why your PC keeps restarting, and can be fixed by using a registry cleaner application to fix any of the damaged registry settings inside your system.