98 Taskbar Phantom Buttons

I work as a tech for a rather large school district which is using Windows 98 as their standard. One problem that’s been encountered is after a screensaver has been on blank buttons appear on the taskbar. I’ve played with the startup, turning off various items, rebooting, and letting the system run with the same results. Not being very proficient in the registry yet I haven’t played there. Has anybody resolved this issue as I’m sure it’s in the OS itself? Any help would be GREATLY appreciated.ThanX
M. Burg