Why don't my cd-rom drives always work?

[bubbagump]

I have a really stange problem under win2k. When I insert CDs, sometimes it just does not recogize the cd is there and gives me a warning message, "Please insert a disc into drive F:." or "Please insert a disc into drive G:." F: is a pioneer dvd-rom drive on the IDE bus. G: is a yamaha 8x internal scsi burner. So I am assuming this is not a bus issue. Most of the time the drives work fine. Also, I know the drives are communicating when this happens because the eject function still works, and I can actually burn a cd through nero or any other burning program. It seems windows access system just does not work. When I restart, all the problems are fixed. Does anyone have any ideas on how to fix this, because it really ticks me off.

Thanks,

Bubba