Missing CD Drive



Running XP Home SP1.

Frequently now, after a boot, my DVD burner is "missing"---it doesn't
show in My Computer which frustrates the hell out of Nero.

CMOS has no problem displaying it, and I find that if I move the
highlighter to it in CMOS and then exit with a Save Windows can find
it.

Anyone have any thoughts on the cause and a permanent fix?
.