I've come in a bit late here but I believe this is relevant. Whilst installing Ultimate, both 64 &32, my screen also froze and the mouse pointer just wouldn't move. No keyboard response, no matter what I did. Until I figured a way around this a hard reboot and start again was the only answer. Now I installed 64 as soon as it was released, (I waited and pounced like many others), md5 and burn confirmed OK. Idid the nuke and start again 5 times and was just about to post a help topic when I decided to try something different. When the freeze happened, I just unplugged the mouse and plugged it back in again. (ps2 mouse). Everything continued without fault from there & has been smokin' ever since.
Now when 32bit was released, I also d/l and installed it. Obviously my machine is a 64bit but I had a spare partition so I thought why not. Anyway, the same freeze and no response. But this time as soon as it happened, I just unplugged and replugged the ps2 mouse and away we went without fault.
I have no explanation for this. Maybe Ultimate is too hot for some hardware pieces and they need to cool off a bit to catch up.
My mouse & keyboard are pretty old whilst the rest of the system has been rebuilt or upgraded. There maybe something in that. Anyway here are my specs if it helps.
mouse & keyboard..old and generic
mobo..GA-M55SLI-S4 with updated BIOS
cpu..AMD x2 6400+ dual core 64bit
ram..4gb 800 duel channel ram (super talent)
gfx..Nvidia 8600gt 512 (gigabyte brand)
h/d..2x320 seagate IDE 1x500 seagate IDE
dvd..LG super multi