Microsoft web sites does not load properly

Good day everyone....brand new here..looks like a very interesting web site....very odd problem for me ...dunno if somebody expert enough to solve that..I am running vista 64 ultimate in dual boot with vista ultimate 32 bits, IE7 is my browser.

I have been googling for the last 2 weeks
3 weeks ago my comp PSU died, and i had to replace it.

After i've done a normal reboot in 64 bits i'm not able to go to any microsoft related website anymore, and also www.download.com is not accessible. And if I put the computer in sleep mode and reopen the internet, everything is working fine!!!.

I don't have this problem in my vista 32 bits machine
I tried the usual stuff like antispyware, antivirus, registry-cleaning.
so I finally gave up and did a complete recovery of my system to a previous date when everything was working OK
But i'm still experiencing the same problem!

Can anyone help me out?..Any help will be much appreciated:wave

Thanks!