Apologies if this problem was solved elsewhere in the Forums. I did a search but didn't quite see any (relatively recent) solutions to my problem. Running Windows XP Pro SP3 with ZoneAlarm Free, Avira AntiVir Premium, Malwarebytes (real-time), SuperAntiSpyware (not real-time) and Comodo BOClean on an older laptop -- granted, might be a bit overkill. As a whole the machine runs fine, except for Mozilla Firefox 3.0.5 (or whatever the latest version is). Slow to start-up, slow to load pages, just overall SLOW. Firefox also has IE Tab and Tab Mix Plus add-ons installed. I know add-ons require additional memory usage. Tried uninstalling Firefox using REVO Uninstaller, cleaning the registry with Glary Utilities Pro, and running CCleaner. Also defragmented the hard-drive (Diskeeper 10), ran CHKDSK with /x /f /r options, and scanned the machine (entire computer) for malware a few days ago. Any errors found were fixed and scans came up clean. Not sure all the cleaning / scanning may have been needed for this issue, but I did it anyway. Re-installed Firefox with the 2 add-ons mentioned above. Also ran Firefox in (what I thought was) Safe-Mode -- the add-ons still appeared in my toolbar. Unfortunately the problem of Firefox running slow still persists. It was there before the uninstall / cleaning and is still there after the re-install. I also experienced the problem after re-booting and with nothing else running. As mentioned, overall the machine runs fine. I also have IE7, Opera, and Chrome installed as browsers, but I currently prefer Firefox. As far as I can tell, I do not have any issues on my machine with running any of these other browsers or any other programs. Any ideas as to what the Firefox problem might be and how to fix it? I heard somewhere that there is a memory leak in Firefox, but I don't know what the solution is/was. Thanks for your help!