The motherboard should be all that's relevant but sure:
Asus P5Q Pro Turbo
4 GB RAM - Corsair something or other
EVGA Geforce 8800 GT
1 DVD burner (sata)
5 hard drives (sata) plugged into all but the first sata port because that caused nothing but headaches for me.
I think you meant that your proc. was an E6750, 4 MB L2, 2.66 GHz, 1333 MHz FSB.
Further, I would not limit your thinking to just the MOBO, I mean you have a 2.66 GHz proc, windows 7 ultimate requites a 1 GHz proc, Plus you have 5 drives which may or may not be connected in the proper configuration which you freely admitted. Also there is a bios update for your board/proc Here
, if that does not fix your problem I would consult your MOBO's manual and see that you have your build properly configured.
I hope this helps you.