Windows XP laptop problem??

I had a worm on my computer. It ate almost everything on my laptop. I took it to a computer repair guy and he fixed it for me, but now, I will be working on my computer and the screen will turn blue for a split second (it says something but i don't have time to read it) and my computer will automatically rebot itself. I have Panda anti-virus and when I run that, it detects two viruses but it cant disinfect them for some reason. If any of you can help me with this, i would really appriciate it. PLEASE HELP!!!