I could successfully use the "Play aginst computer" feature. You might have to reinstall Firefox if it is hanging. I am also using the latest version of firefox and works great both on Windows XP as well as Ubuntu.
Against the Computer
Also, make sure you have the most recent Java plug-in installed with Firefox. This is the only part of the site that uses Java, so it's very possible that if you have an old plug in, that this will be the only place you will have problems.
Java is free and available on the official Java.com Web site.
By the way, this is my first post, so "Hello Chess.com!"
While I'm here, I may as well ask, what is the method by which I can perform a castling move while playing a game against the computer? I'm using the most up to date version of Firefox 2. (Yes FF2 still recieves updates; I stay a little bit behind because I design Web sites. Historically, many Web surfers are slow to upgrade their browsers.)
I've tried multiple times to play chess against the computer, but firefox always becomes non-respondant when I click on the link. I believe I have the newest version of Firefox, but it also didn't work before this one came out. Any suggestions? Thanks in advance.