My computer often restarts, it displays a message that tells me to save my progress (or something) couse my computer is going to restart in 1 minute. And I can't do anything to stop that countdown timer... i tried blocking svchost.exe with ZoneAlarm and it never tried to restart again, but I cant use Internet explorer and some other programs while svchost is blocked. Why is it happening and what should i do?
Note: this only happens in WinXP
and sorry for my terrible eglish

Once again the greatest superhero, The Heat Sink Guy, comes to the rescue.
You have the Blaster worm.
Here are the steps to remove it(you must do it in order to success)
1) Turn of all system restore on all drives
2) Goto symantec website and download the blaster worm removal utility(www.symantec.com)
3) After that install the windows patches for blast worm
4) Restart
If this does not help,i would recomend reinstalling the os.
Hope this helps :)

How exactly do I turn of system restore?

{desktop}properties of <my computer>
<system restore> turn off all

hope it helps