Success!

After uninstalling every weird codec, as well as FFDshow and the Matroshka packs, I reinstalled Windows Media Player and it works. Internet Explorer also doesn't crash when encountering embedded video.

I was on the right track, and my buddy Larry confirmed he'd seen this approach clear up wacky crashes before.

Firefox also works, and looks cool. Tabbed browsing rocks, and most of my bookmarks imported successfully. Overall, impressive and definitely worth downloading. It's also a small download, barely 5 meg or so.