Sevener, could you tell me what makes my firefox 4 eat up all available memory and hang? (It's such a pain, I use it these days only when there's a large file to download; for anything else, it's Chrome.)
Maybe you have multiple extensions installed, many old profiles in the AppData folder, conflict between old versions, toolbars,...etc.
You are using FF4, why you don't update to FF5?
I think, this is the occasion to make a clean installation.
You can unisntall and delete everything related to firefox in:
>Program files>Mozilla>firefox.
>AppData>Local>Mozilla>firefox
>AppData>Roaming>Mozilla>firefox
So, uninstall, delete the folders above and reinstall.
Again, you should be aware about your profile and personal customization that you may wish to keep.
If you wish to conserve special customization in FF, you should backup your profile in the Firefox folder (in the Local Data) and copy it into the new folder after installation.
I also was fan of Chrome but I returned to FF! I loved Chrome skin and omnibar function but there are extensions that provide these features in FF. So, I came back to FF!