win xp and SYMPROXYSVC.EXE???

I need some help, When I use my WINXP and surf the net, after a while, my computer starts bugging and the whole computer starts slowing down till it starts freezing. I say to myself that something is not responding. I sress the ctrl+alt+del and the task manager thingy opens. I look at the process section and the SYMPROXYSVC.EXE is used like at 90someting% and stays there until I end process it. What's wrong with my computer and How do I fix it?