vista 64 is one of the biggest issues
you need to install windows x64 with 1 stick of ram
then do all the updates then stick in the other 2gb.

there is absolutely NO logical reason why anyone outside of a computer lab or 64bit programs need a 64bit OS. (crunches like it but that's their problem)

get back to adecent OS and do a FRESH install... XP doesnt care about 4 gigs of ram and neither does Vista 32bit,, but 64bit can have issues with 4gb of ram until you get it installed and do some updates.


i hate to say this but your cpu is choking.
you were at 3.4ghz and you were already at almost 1.4v
since you went to 400mhz you are going to need 1.5+v to get it to work.
kick the FSB back down to 333
set the vcore to auto just to see what it does.

the mobo is a great clocker but something isnt right here.

set all the voltages except vdimm to auto.
let vcore nb, sb FSB PLL. NB PLL etc etc etc all auto. just to test.

see what happens.

but vista 64 is a fools game my friend there is no reason in this world why you should be using it.

also make sure your running the latest bios.