Hmm. I found the extensions but there is no option to delete anything. Am I missing something? I've highlighted and right clicked, pressed the "delete" button on the keyboard, and nothing.
Well, that's a good question. I'm not in front of a desktop right now, but if you can't delete entries(I thought you could), maybe you can modify them to make them ineffective.
Regarding the profile... I don't remember what it's called in Windows, but you'll want to show hidden files, then look under document settings for your user name, goto the mozilla folder, then find the profile folder which will have a gibberish name. Sorry I can't be more helpful. I can find it myself, but don't remember what everything's called by memory.