Thank you both for the replies. Yes ... I am using the latest BIOS, but the drivers that came with the MB and graphics card. Oh and XP is SP3.
I will go to the store tomorrow and see what the tech guys there have to say about it all. I am willing to try another 790i, but if the same problems persist, I will definitely go for the X48.
I'll let you know how it goes.
Intel Q9450 @ 3.2GHz / Asus STRIKER II EXTREME / 2x2Gb Mushkin Ascent Extreme DDR3 - 1600 / XFX 260GTX, 896 / Thermalright 120 TRUE + Scythe Slipstream 1200 / 2x 130 Gb WD Raid! / 1x WD 640 Gb / 750 TX Corsair PSU / Lite-On Optical Drive / Lian Li PC A-77