If the Plextor is jumper-ed correctly and you still have this problem, pull it.
SATA is still IDE. But we still refer to IDE as PATA too
We don't know the rest of your computer, but intel mobos for the past few years don't natively support PATA. Its an ADD-ON chip. Since almost all IDE drives are now SATA, there is less focus on PATA. The drive itself may also have problems.
I have an odd-ball problem with Win7 and a PATA DVD drive. if a disc is inside, it won't boot or shutdown... something odd (I don't remember, I pulled the drive a long time ago)