W2K AS desktop icons keep moving

Frequently (multiple times per day) if I’m writing a new file to my desktop a random icon on the deskop will momentarily disappear, be replaced by the new file that I’m writing, and then approx 30 seconds to a minute later reappear at another spot on the desktop. Machine is W2K AS running SP1, all the hotfixes, and is the only dc in my domain. This is one of the weirdest things I’ve ever seen.