General :: Restrict Web Access So *only* Firefox Can Access The Web

I'm a terrible procrastinator, it's awe-inspiring annoying and stressful. This in combination with being a information-holic makes the Internet fairly lethal to me; I risk failing my college course because of it, so trust me when I say I'm deadly serious about this.

However, I think you guys may be able to help out, and maybe this will also help some people here with similar problems:

Because so much of my time is taken up with Interwebz, I thought to carefully restrict my internet use. It's not prefect, but it's part of a solution.

To date: I have Firefox and the ProCon extension which uses a whitelist of websites I can access. The extension cannot be uninstalled/disabled and I use a long hex password split into 3 parts, two of which my friends have (so I have to ask my friends for the password parts in order to update the whitelist, hence making it socially awkward to fritter away time online).

So far, it has worked a treat and I'm really pleased with it.

However, this is the problem:

I need to restrict web access so *only* Firefox can access the web. That way I cannot use Chrome/Opera, or even (shudder) use wine to run Internet Exploder.