I know it's been 2 1/2 years but.....about your computer's refusal to boot with a SATA drive plugged in- I have EXACTLY the same problem- different mobo- MSI K7N2, SIIG SC-SAT212-S4 controller card for the new drive, 1TB WD SATA. Computer freezes just before Windows XP Pro starts to load but boots fine as long as the SATA drive isn't plugged in. After booting with only the IDE 120GB Seagate connected I can plug in the SATA drive and it works perfectly. I have tried everything. WD tech support was no help at all. Did you ever figure it out?