Mobo upgrade - windows boot issue!!??

hi all iv just upgraded my computer with a new mobo (asus A4A78), cpu (Phenom X3 720) and gpu (HD4850 512Mb). Im using my existing 2Gb DDR2 Patriot Ram, hard drive and 500W PSU).

Problem is when i start the system up it gets all the way to windows and after a few seconds it briefly (half a second) blue screens before crashing and restarting. I really dont know whats wrong and its frustrating me.

Other usefull info..... the express gate thing at the start of boot up doesnt work, the Ram im using isnt listed in the mobo manual but i doubt thats the issue. Iv got the case open and the CPU temp is 46 degrees centigrade, Mobo temp is 27.

Oh and as this is an upgrade iv had to rebuild the old system to get online to ask for help :-( ahhhhhhh lol please help

If u change motherboads u have to reload windows. That is if the Chipsets are different.