Windows XP Virus problem

In Some windows XP PCs i am facing a problem that, when i open My Computer,explorer, control panel it will not open . instead of that all desktop icons will diappear for two sec and will come back. Since it is affected in more than one PCs i think it is a virus. But i have Norton 2003 with latest virus defenitions which is not identifying any virus.Now what i am doing is formatting and reinstalling. Anybody has an easy solution to this…? pls reply