I would be tempted to install Qupzilla. It isn't based on Firefox or Chrome/Chromium, so I'm guessing Microsoft wouldn't think to block it, especially considering it's lack of popularity. Or, you could probably download a portable version of Firefox without issue.
Good to know. Thanks for telling us.
Technically, TOR is a computer network designed to anonymize internet traffic via encrypted data relays. Once you have a TOR client running, any app that supports SOCKS proxies can be set up to use it (except BitTorrent apps, and likely apps that use other peer-to-peer networks, such as Gnutella, or eDonkey). Of course, there is the TOR Browser Bundle, which indeed is based on Firefox. However, the TOR Browser Bundle isn't by any means the only browser that can use TOR (although it's probably the best).