Ah yes, this is the most annoying 'feature' in Windows XP.
Use this link for directions on how to reset to DMA mode and force windows to use DMA:
http://neodon.blogspot.com/2006/07/l...ard-drive.html
Note that even though the link has you force DMA mode 6, Windows will automatically set the DMA mode to the maximum the drive supports up to mode 6. Also note this doesn't completely prevent windows from reverting back to PIO mode, but Windows won't set the device to PIO unless it see 6 consecutive errors rather than 6 cumulative errors which is the default.
Be sure to reboot after making the changes so Windows can autodetect the DMA transfer mode for each device.
Jam it back in, in the dark.