Start Firefox in Safe Mode {web link}

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

Start your Computer in safe mode with network support. Then start Firefox. Try Secure websites. Is the problem still there?

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode Starting Any Computer In Safe Mode; Free Online Encyclopedia

Thank you FedMcD, I started Firefox in Safe Mode and the problem of the hang of the computer did not occur in the short term, as it was. So, that seemed to fix it. Now how do I get it to work properly with my Add Ons loaded? I don't really want to stop using them, as they didn't use to cause this hang problem in Firefox, so something in Firefox must have changed. Right? Thank you again, Douglas

It could be the work of one of your add-ons, or it could be Hardware Acceleration. How to disable Hardware Acceleration {web link}

Type about:addons<enter> in the address bar to open your Add-ons Manager. Hot key; <Control> (Mac=<Command>) <Shift> A)

In the Add-ons Manager, on the left, select Extensions. Disable a few add-ons, then Restart Firefox.

Some added toolbar and anti-virus add-ons are known to cause Firefox issues. Disable All Of them.

If the problem continues, disable some more (restarting FF). Continue until the problem is gone. After, you know what group is causing the issue. Re-enable the last group ONE AT A TIME (restarting FF) until the problem returns.

Once you think you found the problem, disable that and re-enable all the others, then restart again. Let us know who the suspect is, detective.

Thank you again, FredMcD, I disabled the Hardware Acceleration first to see if that would stop Firefox from hanging, and it seems to have worked. Been using it a couple days and no hangs. So, seems to be resolved. I'm happy about that because I didn't really want to give up any Add-ons.

Thanks again.  ;-) Douglas

Glad to help. Safe Surfing.