problem with new build

I have just built a new pc for a friend and have run into a problem that I think is the processor but want to be sure before I RMA.

Here are the specs:

antec 900
silverstone op1000 psu
amd 6400
4 gb geil evo one
asus crosshair mobo
western digital 320 gb HDD
samsung lightscribe dvd burner
BFG 8800 GT G92

Here is the problem:

When I went to install vista 64 bit I had an error message and had to start over (dont remember the error code). Next try went smoothly but upon installing vga driver and reboot I recieved another error message saying that windows cannot boot, missing a file insert windows disc and select repair. So I did that and it said unable to repair. So I tried to install vista again and recieved more error messages. basically it takes about 3-4 tries to install vista to actually get it installed and then once installed it will not reboot without an error message saying that files are missing.

So thinking it was a ram/hardrive/dvd drive issue I replaced all with known working/compatible parts and still recieve error messages.

So I decided to try windows xp 32 bit home and also recieve error messages on install saying missing driver, but am able to install and boot xp fine. In XP I have no network access so I open the device manager and see about 6 unknown devices without drivers and a pci memory controller without a driver. I know the memory controller for amd is on the proc this is why I am thinking that it is a processor problem (and I have pretty much tried eveything else except the mobo). I am pretty sure that the mobo is ok because I just pulled it from another build that worked fine (mobo sat in static free bag for about 2 months).

I have tried removing all that is not required to run the system like the front usb, firewire, front audio, all but 1 gb of ram. I am stumped anyone have any ideas?

Any help is appreciated.
Thanks
Jason

Well, this forum is made of a majority of intel users.

When you had xp installed & running, did you install the mobo driver cd? You must or else there'll be yellow question marks in dev. mgr. Also, there are 2 drivers from amd. One is for cpu. Another is for cool-n-quieter. They must be installed. C-N-Q may be optional if you overclock.

You think it's the cpu. I think it is either the mobo or software. I usually lean towards the latter.