High CPU usage with no web response
Windows XP SP3, Intel Pentium M 2.00GHz, 2.0GB RAM, ATI Mobility Radeon X300 Computer works great with every other program, even online software updating so long as it doesn't use 'Firefox 45.0.1'. Went so far as to uninstall and downgrade back to '43.0', same problem. Upon opening Firefox, CPU usage shoots to 80+% consistently and no webpage response, not even a tab title. Left computer on for hours at a time, cpu usage and internet response remains the same. Tried to restart in safe mode but won't self close the process in task manager. Have to end process in task manager and won't start in safe mode. Tried to update extensions and add-ons but can't access website to do so. Have disabled all extensions and add-ons and problem still present. Currently using Chrome with no online problems.
Wšě wotmołwy (2)
Hello RoninWolf, please try a Clean reinstall.
This means you remove your Firefox program files and then reinstall Firefox. This process does not remove your Firefox profile data (such as bookmarks and passwords), since that information is stored in a different location.
To do a clean reinstall of Firefox, please follow these steps: Note: You might want to print these steps or view them in another browser.
- Download the latest Desktop version of Firefox from one of the next links : https://download-installer.cdn.mozilla.net/pub/firefox/releases/45.0.1/ OR from : https://ftp.mozilla.org/pub/firefox/releases/45.0.1/ and save the setup file to your computer.
- After the download finishes, close all Firefox windows (or open the Firefox menu
and click the close button 
).
- Delete the Firefox installation folder, which is located in one of these locations, by default:
- Windows:
- C:\Program Files\Mozilla Firefox
- C:\Program Files (x86)\Mozilla Firefox
- Windows:
- Now, go ahead and reinstall Firefox:
- Double-click the downloaded installation file and go through the steps of the installation wizard.
- Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.
More information about reinstalling Firefox can be found here.
WARNING: Do not use a third party uninstaller as part of this process. Doing so could permanently delete your Firefox profile data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. These cannot be easily recovered unless they have been backed up to an external device! See Back up and restore information in Firefox profiles.
Any luck ?
Thank you.
Did this when i downgraded, then upgraded back to 45.0.1 the same way. No firewalls and/or proxy changes in years, just started happening this past week.