DVD drive disappears when swapping disks

[the-bullet]

Hi all. I have a Sony DVD drive that disappears from My Computer and Device Manager when I swap disks over(cd's or dvd's). This doesn't happen everytime, maybe about 4 out of 10 times. The lens is clean, it happens with various cd's /dvd's. When I reboot things are back to normal. The drive has never disappeared during any other circumstance, such as during games, movies music etc, only on swapping disks. All cables are secure, and I have tried removing the relevent ide channel from device manager and rebooting. All drivers are current and installed.But still this annoying problem persists. Any help would be appreciated. Thanks

P4 3.2e
Asus P4C800 Deluxe
2 x 512mb 3200 ram
2x HD's both 80g NTFS
Ati 9700pro graphics
Audigy 1 platinum sound card
Sony Dvd drive
Plextor CDRW
No overclocking
Windows XP SP2