I found a solution to this problem at least for p5Q deluxe motherboard and since it took me weeks to figure it out after countless hours on the web and event viewer I thought I might try and save some other people a lot of headaches and post what worked here. First what didn't work updating drivers, updating the bios and finally a clean reinstall of Windows. What did work? Clearing CMOS RTC RAM on the motherboard which basically sets the bios back to the original minus the glitch. Then updating the bios to the most recent Bios update I finally came across this on the ASUS forums. I can't believe I did all the above before I tried this but there you are live and learn. Hope this helps others a whole lot of unnecessary reinstalls.
Thanks, I have found a lot of useful information on this forum so thanks for the replies. Just trying to do my bit to help those in the vista endless reboot nightmare. Cheers