WordPress Style Sheet

Yes, I now the theme looks kinda screwy. For some reason my style sheets have stopped working. Doesn’t matter which theme I use, the style sheets don’t work. I’ve searched the Internet for clues about what the problem might be, but so far all I’ve found is self-righteous programmers patting total idjits on the head for finally figuring out that they have to upload the right files to the right directories.
My problem wasn’t with a new install. This install has been on the server for awhile, and it’s been working fine. I suspect it has something to do with the fact that my hosting service has been upgrading their version of PHP. I’ve had trouble across the board ever since.
But… I don’t have the problem with stylesheets on any of my other sites, and they’re all on the same server. I don’t even have this problem with any of the other blogs on Wicasta.com. Just the main blog here. And before any self-righteous programmer can start patting me on the head, I’ve already re-installed WordPress in case any files had become corrupted.
I’ll figure it out. But if you have any ideas, I’d love to hear them.
Update:
Problem has been corrected. Turns out the problem was the SezWho plug-in. Once it was deactivated everything started working fine again. Now if I can just find another decent contact plug-in (Enhanced WordPress contact form hasn’t worked right since the release of WordPress 2.7).