Drat, I loaded up the new Firefox update, released yesterday, on my old XP machine and first it crashed several times on just the first few Web pages (if a browser crashes when you open TechMeme you know something is nutty). Now Firefox isn’t opening at all. I’d avoid this update until more people test it.
UPDATE: Looks like it is some sort of interaction thing with Google’s Web Accelerator. I removed that and Firefox started working again. I’ll work with the Firefox team to figure out what’s at fault here.