HELP!! - Possible Virus - blank menus

Basically what happened is I came home from work, shook my mouse to take the computer out of screen saver and as soon as it came out, my computer restarted itself. When it rebooted, the initial log-in showed my icon and a text box to input my password, but didn't display my username or the dots for the password. Finally just typed it without watching it and was able to log in.

***When I logged in, everything looks normal except if you try to bring up a menu, EVERYTHING IS BLANK. Every single one of my menus is BLANK - NO LETTERS / WORDS. When I open system preferences - icons are there but NO WORDS. If I click on a preference icon, it brings up the window for that preference but everything is blank - buttons, options, settings, etc. When I try to open Safari - it will not open, just bounces like it's opening and then stops and closes. The only thing I can actually see is files in finder.

If anyone has ever heard of this problem or knows how to correct it, please feel free to chime in because at this point I'm ready to wipe and reinstall OSX Tiger. I work in the IT industry and are fully aware of how viruses can infiltrate system and have not done anything sketchy along those lines. The only thing I have downloaded lately is music from Limewire (using acquisition) and I believe it may have come from that.

I know that everyone says there aren't any viruses currently out there for OSX, and I have said that for years myself, but my ibook started acting extremely wierd yesterday and I genuinely believe it is a virus.

 

I've rebooted several times, no help

 

What are the commands to do that? I know I do it from command line