Vista running slow on Core 2 Duo, 4 gb ram and 8800 GTS, plz help

First here are my specs:

Window's Vista Ultimate 64 bit version bought of newegg as OEM

Intel Core 2 Duo at 2.13 GHz

MSInForce 650iSLi Platinum Motherboard

4 GB of RAM

NVidia GeForce 8800 GTS (320 MB)

80 GB WD hard drive at 10,000 RPM (Raptor)

700 watt power-supply (OCz)

So basically I built my computer yesterday and installed all the vista 64bit drivers and then installed all the widows updates yet my computer is running so slow that I had to use my XP machine to post this because it is that bad. It was a clean install and I activated windows right away yet even when I have simply one window open where it be with Aero on or off, it comesto a crawl (even in safe mode it runs slow). Both cores are anywhere from 50%-100% is use at any given time. Another odd thing is that Vista will not rate my system nor can I flash the BIOs to update it. I knew a 64 bit version of Windows would have it's issues but this is crap. It took me 30 minutes to install msn messenger after it was already downloaded! I know I have plenty of juice to run Vista so there is no reason why a Core 2 Duo can't smoothly run vista when I've had vista running on my old P4 3.0 Ghz with 2 GB of ram and a GeForce 5200 w/ 128ram. I can't seem to find a solution to this problem. Any help would be very greatly appreciated. Thank you.

My guess is that you probably have a program thats screwing up and hindering your performance. Have you tried going into the Task Manager and ending some of the processes?

Other than that I don't understand how you can have ANY performance problems with that rig. Its almost identical to mine except I have an E6600 cpu and 600 watt OCZ psu and I run it flawlessly.