IE not displaying (ignoring) CSS stylesheets

Weird problem with a computer that I am cleaning for a friend. IE will not use a stylesheet as specified by a webpage. Ignored the problem for a bit and cleaned the system: installed WinXP SP2, installed Windows Defender, install and run Adware and Spybot Search and Destroy, and clean up a bunch of temp files. Also, upgraded the driver for the graphics card as there were some issues with that. Now back to the IE problem. Went back to IE and problem was still around. After looking around I noticed that IE has some accessibility options that I never noticed before.

Internet Option -> General -> Accessibility (button at the bottom)

• Ignore colors specified on Web pages
• Ignore font styles specified on Web pages
• Ignore font sizes specified on Web pages

Unchecked all of those (not sure why they were checked) and back in business...