Opera stole file associations, won't uninstall

[mstevens]

I installed an Opera CAB file to play with. Thus far, I see little reason to prefer it to PIE. This is especially true since it screwed up file associations for a range of files. For example, now if I tap on a URL in an email it attempts to launch Opera and gives me an error message instead of opening the URL in PIE (or even in Opera). Opera does not appear in my uninstall list, so I can't figure out how to get rid of it and restore file associations in the registry. This is pretty obnoxious behavior on the part of any program. It should ask before changing any of my settings!

Any idea how to get back to where I was without a hard reset?