My windows xp has a lot of viruses and now it shut down automatically by itself

Check the charger of your laptop if there is any place that has problem or cut? check the voltage of your laptop whether is the same thing with the charger. If everything are fine, then reload your operating system, because I have noticed this problem with my clients. Good luck

your PC got a Dangerous Virus.
the Virus Shuts down or resets The PC in order to spread (in whole of the PC) more.
so download and install a new anti virus.(Like Nod32 or Norton etc)
then update it and run a full scan.

try and repair the Operating system of your computer it will solve your problem or you can check all the running processes in the task manager must of time it do cause the system to slow.

Your computer may be Virus'd
Try tapping the F10 key as the PC is booting up,,and choose safe start.
If you can get that far, you can use system restore to restore to some previous date.
Then Scan for Virus and Malwear.

check virus in your computer with a updated virus remover.

hiiiiii friends
some virus on your pc .....remember you format it total driver........

Recovery SettingsOne of the things that is quite different about Windows XP compared to Windows 9x (9x is shorthand for Windows 95, Windows 98, and Windows Me in all their various versions), is that one can control how it responds to certain critical errors—those that cause the infamous Blue Screen of Death (BSOD). In Windows XP, the default setting is for the computer to reboot automatically when a fatal error occurs. If that fatal error only occurs when you're shutting down, the system reboots automatically.
If you haven't changed any of the system failure settings, you should be able to see the error by looking in the Event Log. But a better long-term solution is to turn off the automatic reboot so you can actually see the error when it happens—chances are it will tell you enough about itself to let you troubleshoot further. To change the recovery settings to disable automatic rebooting:
1.
Right-click My Computer, and then click Properties.
2.
Click the Advanced tab.
3.
Under Startup and Recovery, click Settings to open the Startup and Recovery dialog box.
4.
Clear the Automatically restart check box, and click OK the necessary number of times.
5.
Restart your computer for the settings to take effect.
Now when you go to shut down and a fatal error occurs, you'll at least see it and it won't cause an automatic reboot. You still have to sort out what's causing the problem, but that gets us to the next section quite nicely.

Start the computer in safe mode (tap F8 immediately after turning it on until you see the option of how to boot)

If it successfully boots into windows, you have an issue with either driver conflicts and/or viruses. If it still restarts itself, you most likely have a hardware issue (bad hard drive, motherboard, etc)

dear sachin
please do a system scan for viruses (update your anti-virus first)in safe mode by disabling system restore.if the problem still persists clean your ram and install it again.report back your findings

Assuming you have an anti virus and spyware programme installed:- you need to turn off system restore first as it backs itself up and then run your anti virus programme, prefferably in safe mode, restart the pc and turn system restore back on.