hello mate, I assume that on the taskbar it is showing u red icon with 'X', i face this problem in many computers in the company as it is basically a notice that ur computer is hit by trojan, as an IT officer, the solution for this problem is to download a software called smitfraud from

http://www.afterdawn.com/software/desktop_software/desktop_security/smit...

after downloading save it on ur desktop run ur system in safe mode double click Smitfraud, it will open in DOS and press 2 to clean.

I hope this information will be useful for u.