throbbing light machine

guys, my iMovie is freaking out, and my google-fu isn't leading me to helpful answers. I just cleaned out my FontBook - I tend to collect pretty free fonts, and as of last week I had over 800 installed. Some of the fonts I deleted were fonts I had previously used in vidding. Now, when I open the "Show Fonts" display panel, it's cut in half, displaying three fonts, four colors, and three sizes, instead of the complete range; when I go to the Preferences menu and attempt to open Fonts, I get a white square and have to quit the program. I've restarted the iMovie project, the program, and my computer, and still no joy. Any ideas?