I'd encountered many problems lately with the FF3... I've switched and currently using the safari now.
FF3 seems a fiasco for me. They wanted to make sites to load faster but if a website won't load as fast as it's supposed to the browser won't load it at all. The only good thing about it is that it's more secure than other browsers.
Does the problem just happen? Or since your first install? do you have many apps running on system tray? Or maybe because you have small RAM
1. Try re-installing Firefox 3. 2. Remove unwanted add-ons. 3. Remove unwanted toolbars. 4. Type about:config in the address bar and find these values. a. network.http.pipelining, b. network.http.proxy.pipelining and c. network.http.pipelining.maxrequests. Change the value of the first two to “true†and the last one to a value of “30″. Finally, right click and add a new integer. Name this integer nglayout.initialpaint.delay. Make the value “0″. 5. Get FineTune for Firefox 3. Link: http://firetune-for-firefox.en.softonic.com/ 6. Get more RAM! Here are some more Firefox tricks: http://www.lifehack.org/articles/technology/15-coolest-firefox-tricks-ever.html