I've experienced frequent cases of Firefox 2.0 hanging on my machine. I can't pinpoint the cause at this stage, but I have a hunch that it may be in relation to filling up HTML forms or opening new tabs.
Thankfully, the MozillaZine knowledge base has lots of useful articles on possible causes and recommended diagnostic steps.
It's interesting to note that the official Google Toolbar is listed as a possible problematic extension, with memory leaks being one of its drawbacks (see screenshot below). I'm going to try and disable the Google Toolbar extension as part of my diagnostic test. There's a note on this page that indicates that the Google Toolbar spellchecker interferes with Firefox 2.0's built-in spellchecker. It's a good thing that extensions can be disabled as it allows for quick diagnostic tests without the need to uninstall.
- What's the difference between a crash and a hang? A crash is the term used when an error occurs and the program (e.g. Firefox) closes itself. A hang is the term used to refer to cases when the program is running but stops responding to user input.