Firefox Won't Load CSS Properly?

My sister's computer (Windows XP) was having trouble with IE6 since she got it. It would not load CSS files, so it wouldn't show webpages properly. She installed Firefox and it worked fine, so she started using Firefox.

Last night she visited and I noticed that she had a previous version of Firefox, so I suggested she use our cable internet to get upgraded to the latest. She thought that was a nifty idea, so she upgraded... only now Firefox wouldn't load CSS anymore and every website that used CSS looked bad.

So we started a marathon troubleshooting session with her friend A-- and later his uncle (both of whom work at Microsoft). Early in the troubleshooting we focused on the browsers, but eventually we figured out that it had to be something else. My sister installed Netscape and Opera, and both of them worked fine, just like the older version of Firefox.

After trying everything we could think of (firewall, anti-virus, possible spyware problem, maybe we need to get an exorcist) we started checking through the accessibility options. Eventually we found that in the control panel, under Accessibility Options, in the Display tab... my sister's computer had "Use High Contrast" selected. When we took that away, the CSS loaded on both IE6 and Firefox.

The difference in the computer itself was minor. It had apparently been set on High Contrast a long time ago, possibly by the vendor (she bought the computer new). I admit it was one of the strangest problems I'd ever seen on a computer. I figured I would blog about it so that we'd have a record of it in case anyone else runs across a strange "browser won't load CSS" or "websites don't look right" problem. I Googled the heck out of this last night and never ran across a solution.