Firefox using lots of CPU time

I'm using FF 2.0.0.1 on XP Pro SP2. I have these extensions:

- Adblock 0.5.3.043
- Adblock Filterset.G Updater 0.3.0.5
- Autohide 1.1.4
- BBCodeXtra 0.2.5.6
- BlockSite 0.5
(Disabled)
- Bookmark Backup 0.4
(Disabled)
- British English Dictionary 1.19
- ChatZilla 0.9.77
- Cooliris Previews 2.1
(Disabled)
- CustomizeGoogle 0.55
- Disable Targets For Downloads 1.0.1
(Disabled)
- DOM Inspector 1.8.1.1
- DownThemAll! 0.9.9.7
- Extension List Dumper 1.7.1
- Fasterfox 2.0.0
- Flashblock 1.5.2
- Forecastfox 0.9.3.1
- Foxmarks Bookmark Synchronizer 0.84
(Disabled)
- Greasemonkey 0.6.6.20061017.0
- IE View 1.3.1
- Menu Editor 1.2.3
- Organize Status Bar 0.5
- PermaTabs 1.4.0
- Tab Catalog 1.1.2006110601
(Disabled)
- Tab Mix Plus 0.3.5.2
(Disabled)
- Tabbrowser Preferences 1.3.1.1
(Disabled)
- Torbutton 1.0.4
(Disabled)
- Undo Closed Tabs Button 2.0.0
- VideoDownloader 1.1.1

I frequently find that FF, once it has been running for a while, gets to a point where it is eating up ~25% of my CPU time whilst not doing anything. This continues until I restart it. I have reinstalled and it had no effect.

Has anyone had a similar experience? Does anyone know why this happens?

Do you have any tabs open when check the cpu? Some webpages are cpu intensive as well as flash games.

I do have tabs open, but they are all simple pages - no flash or java applets.

Try running Firefox in safe mode to make sure it isn't an extension(s) causing your problem...

http://kb.mozillazine.org/Safe_mode

Problematic extensions
http://kb.mozillazine.org/Problematic_extensions

Thanks for the problematic extensions list. I have disabled Forecastfox and it seems to have done the trick - time will tell though.