I have the same problem!
I was about to post and I saw this.
I updeated win 7 64, on june 15th, like any other time. The update was beefy as many updates seamed to accumulate to 100+mb upgrade.
After I reset the computer, windows logo freezes and so does the computer. At random, and I mean random attempts, it will log on again, but will log fine if I chose shut down, instead of reset. Reset is sure way to freeze my computer.
It took me ages to figure the above. I have dual boot win 7 64/xp 64. After updating 7, I couldnt log to xp as well. Only safe mode, and only randomly at that.
I used easy bcd to remove win xp from booting options. I'm too afraid to reset/shut down computer now, as it works flawlessly as long as I stay logged on.
I was waiting for another update to fix this, but I decided to post my problem in hope someone might have an actual solution- not a guess like mine.
I spent hours yesterday trying to log in hopelessly. I finally gave up at 3 am, and win 7 booted fine this morning.
I have custom built comp from 2008. It worked flawlessly since i updated from vista to 7 about 2009. I have asus p5q (no extra letters) motherboard, intel core 2 quad @ 2.4ghz OC to 3ghz (10+ hours stable on p95) and worked fine until the mentioned update. gtx 460 gpu, 4gb ddr2 800 ram. I hope I didnt miss anything else relevant.