Windows 7 - New Proc, now Windows 7 64 bit won't work

Hey there, I recently purchased and OEM of win 7 64-bit and ran it for about a week. Worked good, liked it alot. Well Yesterday I upgraded to a quad core and now i get this error message.

windows failed to start a recent hardware or software change might be the cause. to fix the problem

1. insert your windows installation disc and restart
2. choose your language settings
3. click repair your comp

status 0xc0000225

info: and unexpected error has occurred

the bootup session goes like this
1. BIOS
2. Boot From CD (DVD)
3. press any key to boot from CD
4. Windows setup, Progress bar
5. error message

first thing i tried was put the old proc back in, no luck. Next i tried Win XP 32bit and that was successful. Formated and tried burning a copy of my Win 7 disk on the lowest speed x2.5, no luck.

Next i tried uninstalling everything but the basic hardware needed, such as one stick of ram, turning off the Raid and only using one hard drive, unplug all usb devices, etc... no luck.

I'm at a loss here. ive reinstalled xp and started testing everything i can think of. Ram test, hard drive test trying to find somthing wrong but... no luck.

Just for kicks, i tried installing it on my wifes laptop and it got a little further. Untill an error message says this is not a 64 bit computer.

My Specs are

1. Intel core 2 Quad Q8300
2. 2 gig of Corsair XMS2 6400 1024x2 800mhz
3. Nvidia EVGA GTX 260 896 MBytes
4. EVGA 750i sli mobo
5. WD Raptors 70g x2 Raid 0

Thanks

If you replaced the old processor, Windows 7 should start up on old HD.

Try writing the ISO to bootable USB flash stick: Windows 7 USB/DVD Download Tool

Reset the CMOS: Clear CMOS - 3 Ways to Clear the CMOS - Reset BIOS

Check the SATA controller setting. Try ACHI first, then IDE mode if necessary.

That ACHI thing can get you!

Have you checked for a bios update for the new CPU?

Problem Fixed...

Thank you so much fellas, I want you to know I tried all the sugestions above and the winner goes to Saltgrass. After flashing the bios, Windows 7 started the install... Thanks for the other recomendations, cause i learned alot. I've actually never tried booting from a usb before, very cool. also learned that the 7 series mobos don't have ACHI settings, way to go Nvidia,

Thanks again

laters