BleepingComputer.com: Vista freezes completely on login screen

Hey all, I'm posting on behalf of a friend here. Recently her desktop's begun freezing on boot at the login screen, but only after being turned off all night. When she reboots it and tries again, it works without a hitch. There aren't any error messages.

Googling's been of no help, and it's especially difficult to fix since it only happens after it's been off for a long time. I'm not sure how else to help her. Is anyone here familiar with this problem?

The computer is a HP Slimline s3700z with the following specs:

I didn't see an edit button, but here's an update:

As of today and yesterday, her computer has started to freeze in the middle of the day. It hasn't begun to do it often, but it wasn't happening before. When it freezes, keyboard commands don't work, nor the mouse. She has to force shut down by holding the power button.

She works from home on her computer so it's really important we get this figured out!

EDIT: Removed link to malware log, not allowed nor used in XP forum, no evidence of malware problem ~ Hamluis.

This post has been edited by hamluis: 09 May 2011 - 07:45 AM