When you decide to upgrade back to the latest Firefox version and the problem re-occurs, perform the suggestions mentioned in the following articles:

• Clear Cookies & Cache
• Fix problems connecting to websites after updating Firefox
• Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems
• Update All your Firefox Plugins -> https://www.mozilla.org/en-US/plugincheck/
  • When Downloading Plugins Update setup files, Remove Checkmark from Downloading other Optional Softwares with your Plugins (e.g. Toolbars, McAfee, Google Chrome, etc.)

@ mha007 Thanks for your reply to my difficulties. I have tried all of the fixes and upgrades you had referred to, and still have the same lagging issues. I know it is not Firewall related as I am using Firefox 10 on 2 of my other desktops running Win 7 on my same local network without issues. I have even uninstalled Firefox with the update for version 10, re-booted the PC and downloaded and installed a fresh application for version 10. I'm stumped here for now, so I'll go back to 9.0 until I am able to find a solution.

-> Update Firefox to the latest version 10.0.1

• How to install Firefox on Windows

Perform the suggestions mentioned in the following article:

• Firefox hangs or is not responding - How to fix

Check and tell if its working.

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode

Create a new profile as a test to check if your current profile is causing the problems.

See "Basic Troubleshooting: Make a new profile":

• https://support.mozilla.org/kb/Basic+Troubleshooting#w_8-make-a-new-profile

There may be extensions and plugins installed by default in a new profile, so check that in "Tools > Add-ons > Extensions & Plugins" in case there are still problems.

If that new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.

See:

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Ran ver 10 in safe mode without plug-ins/add-ons and responsiveness was still laggy/sluggish. When trying to close the program, it cycled trying to complete the close, but couldn't close. Almost like an endless loop attempting to complete the command. Tried with as new profile as suggested and ended with the same result...lack of responsiveness in the application. There must be something about this particular machine that Firefox 10 does not like, and behaves odd? It's not a big issue with me, as I can live with ver 9.0 as I have switched back to now for this machine, but still curious why the odd behavior for this setup? Thank you for all of the suggestions at an attempt to find the problem, the assistance was appreciated.

Do a MALWARE check with these Malware Scanning programs. You need to scan with all programs because each program detects different malware. Make sure that you UPDATE each program to get the latest version of their Databases before doing a Scan. Also, Close All other Applications (softwares) before Starting to Run Scans.

• Malwarebytes' Anti-Malware -> http://www.malwarebytes.org/products/malwarebytes_free
• SuperAntispyware -> http://www.superantispyware.com
• Ad-Aware Free Internet Security -> http://www.lavasoft.com/products/ad_aware_free.php
• Spybot Search & Destroy -> http://www.safer-networking.org/en/index.html
• Anti-Rootkit Utility TDSSKiller -> http://support.kaspersky.com/faq/?qid=208283363

Check and tell if its working.

Just received and installed update to Firefox ver 10.02, and voila...all the symptoms of the problems I was having have corrected themselves?? Still curious of what the issue was with my install in Server 2008? Have the latest Firefox installed in Fedora 16-64bit and runs without issue. I dual-boot this machine between the two O/S's Again, thanks to all those who offered suggestions/advice on my issues.