Major Problem with My Computer!

I have a Windows xp, service pack 2, Hp laptop. When I turn it on, i log in, then it shows my background, but nothing else, no icons no start menu. I try cntrl alt delete, nothing happens, its just stuck there. We earlier could not open any antivirus software, A comcast support woman it MAY be a worm? So What can i do to fix this, Safe mode? when im in safe mode, should i click the system restore, or just try to fix things from safemode?? please help, my laptop is like almost gone.