No DVD Support

Over Thanksgiving weekend I reformatted my computer and reinstalled
windows xp home sp2. Since that time, I've been having trouble with my
optical drive(s). For some reason my drive doesn't read "pressed" DVDs.
This includes all video discs as well as some data discs. I can read
burned discs just fine.

First I thought the drive was shot so I swapped it out with another and
got the same results. The original drive is now in an external
enclosure and is reading all discs with no issues when connected to my
laptop. However, that same drive in the same external enclosure (USB)
will not read DVDs when connected to the desktop pc.

I reloaded the latest VIA drivers for my chipset hoping that might fix
it, but no luck. That was my best shot. Anyone have an experience like
this before?

-Dylan C

System details:
Abit AV8
Athlon 64 x2 3800
1 Gb RAM
Optorite and Sony DVD-RW drives
WinXP Home SP2