Desktop Icons

I have a user in our company that his icons setup exactly how he wants them on his Windows 98 desktop. Everyonce in a while, these icons will rearrange themselves when he reboots or boots up his computer in the mornings. This activity is spiratic and I can’t pin it down to exactly when or how it happens. Any ideas on how I can make these icons stay put? (I have the auto arrange option unchecked)