when my FF acts odd I make a new profile to see if it is acting weird also.

Since it is the same after reinstalls , I wonder if it is something in your saved profile files - that is where your own particular settings , cookies, bookmarks area saved.

You can open this link in IE to do the steps if you want to try it- but you have to close FF to make the new profile.

It is pretty easy but if you do it make sure it 'asks you at start up' which profile you want to use (the default or the new one if you make one
- it just makes it easier for when you decide to use the new one all the time -or delete it. If you decide to use the new one you can import the saved or backed up bookmarks.

But read all the info about it first - the XP part is below the Vista & Win 7 section.
http://support.mozilla.com/en-US/kb/Managing%20profiles

Or installing the Flock browser might be simpler
it is nearly the same as FF and I believe it will ask to import FF bookmarks & settings for you. The default homepage is more focused on facebook & other social networking sites , but you can remove those and use the home page that you prefer.
http://www.flock.com/


for IE import of bookmarks/favorites
Open IE and go to File, down to Import/export
from another browser , and FF shows for me so click that-
I already have mine imported so didn't want to do it again
but it should work fine from that point on.