But other programs still running fine? On my OSX partition only 4 free gigs left. Could this be the problem? I miss firefox, but alas I'm stuck using chrome.
First of all, a general rule of thumb is to always maintain 10% of your HDD capacity as free space. This will help with general computing.
Secondly, Firefox has issues. There are memory leaks galore, and it's losing steam against more modern browsers like Safari and Chrome. I was like you and stubbornly kept using Firefox because it had extensions and it was familiar. Now that Chrome & Safari have extensions too, there is even less reason to keep using Firefox. I couldn't handle Firefox constantly hanging (especially when loading pages with Flash) and its memory leaks, so I switched to Chrome (although I do have some problems with it).
One nice feature w/ Chrome is the ability to sync your browser with your Google/Gmail account (i.e., bookmarks, preferences, extensions, etc).