Unplug all USB and anything that is not stock with that PC.
Yesterday my desktop with Vista Home Premium began to not boot up past the Vista loading bar, it just ran and ran and ran and never went anywhere. I tried booting the Last Known Good and got the same result.
I tried booting into Safe Mode w/ Networking, Safe Mode w/ Command Prompt, and plain ol' Safe Mode and all get stuck on Windows\system32\drivers\crcdisk.sys.
I tried booting from my Vista CD, it goes through loading some files with a progress bar. Once that finishes, it goes to the Vista loading bar, then I get a BSOD. IRQL_NOT_LESS_OR_EQUAL. 0x0000000A (0x74042346, 0x00000002, 0x00000000, 0x888BA8D7.
Before the problem started, here is what I was doing. I hooked up my scanner to scan a couple docs then disconnected it. I went to shut down and there were Windows Updates waiting so I clicked the red circle icon with the Windows Update icon. I saw it had 11 updates to install and I left the room. The problem started when I went to reboot the machine a few hours later.

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