Unfortunately, I'm having the same exact problem with a P6T Deluxe. Using 3 x Corsair Dominator 2GB 1600MHz 8-8-8-24 memory. So far I've tried the following:
-Reset CMOS by using jumper and battery removal method.
-Unplugged everything (all SATA connections, USB headers, etc), leaving...
everyone go get yer key @ https://www.microsoft.com/betaexperience/productkeys/win7-64/enus/default.aspx (for 64-bit obviously). Just keep refreshing, the blog lies!