Here you go, the instructions are here: http://techdows.com/2011/06/downgrade-firefox-5.html

It worked for me!

Thank you thank you thank you! I did just what you said and my thumbnails are back and all is right with the world. Thanks again!!!!!!

No problem, glad I could be on the helping end for a change, lol.

Just a heads up, though, they say the older versions are not gonna be as secure, as apparently they're gonna stop putting out new security released for old versions. So if the next Firefox version is more tolerable for you, it might be smart to update.

I've found that it's better to wait a bit until they fix all of the compatibility issues and bugs that happen in the first few weeks.

Firefox 5.0 is a security update for Firefox 4.0 & 4.0.1, which aren't supported any longer. You're not doing Firefox users any favor by linking to websites that promote reverting to Firefox 4.0 versions. Firefox 3.6.18 is the correct version to recommend, per Mozilla, for users who want to downgrade from Firefox 5.0 - right now.

As far as "compatibility" issues with Firefox 5.0, it is (and always has been) the responsibility of add-on developers to keep the stuff up-to-date with new Firefox versions, as they are released. Other than to Blocklist add-ons that are causing an extreme amount of problems (like crashing Firefox) with Firefox, Mozilla doesn't get involved with "compatibility" issues.

Yes, from now on I won't leap right in and update until I know the bugs are gone. I plan to keep an eye of Firefox 5 or future ones to see if the Google Toolbar comes back, since there are security concerns. Thanks again for your help!!! My husband was happy I didn't have to send up a flare and have him come running, especially since he's not a Firefox user, lol!