I rebooted in safe mode with networking, then I disabled *all* startup programs to see if it was a driver triggering the problem. No luck.
I uninstalled AVG 7.5. When I tried updating the virus definitions, it indicated a problem and suggested I reinstall it, so I just uninstalled it.
I've scanned the computer using SpyBot to see if there was something messing with it. Nothing.
Any thoughts on what else I can try to get out of it not letting me boot in regular mode and defaulting to the safe mode selection screen?