my web browser opens and it closes after few seconds. also, i cant open the command prompt..im not getting any error message..running my spyware didnt solve the problem

Are there any error messages? could be someone has tampered with the registry or a virus :) would suggest installing an AV program and running a system scan to be safe. Once thats cleared i would suggest repairing your windows (if it's xp) just to be safe.
hope that helps.

whats your browser??? IE i assume...
your computer has a virus.. one app connot fix the problem....
make sure you have anti-spy and anti-virus and anti-adware..

my recomended FREEWARES
anti-virus:
AVG free
anti-spy:
sbybot seach and destroy
anti-adware:
Ad-adware SE

just google it or find it in the PC app section.. just click on my sig,, ;)

also start using a good firewall, if u dont already
i use ZoneAlarm, its reliable and also updates itself