FireFox Hangs

Hi,
I am using a Lenovo laptop with i5 processor, upgraded its OS from Windows 7 Home Basic to Home Premium. I also have Norton360 and TuneUp Utilities (latest versions, 2012).
Firefox 11 was running OK, but because I had many add-ons, I decided to uninstall it and get myself a fresh browser. So, I did that with Revo Uninstaller Pro.
After the re-installation, every time I run Firefox the address bar doesn't take any input from the keyboard. The program itself accepts the mouse clicks on menus for a short time, before it freezes completely!
After I press Ctrl+W, it adds +1 to the number of opened tabs. Firefox opens 2 tabs on start up, one for the homepage and the other on Mozilla site. But it asks me "do you want to all the 3 opened tabs?". It does the same when there is only one tab opened.

Thanks for the advice.

I did that, it didn't solve the problem but I discovered something. When I write a new web address after the one that already exists, it works. For example, if my homepage is Google, then I write www.google.comwww.yahoo.com, then delete Google and press enter, Firefox doesn't hang. If not then it will freeze.
That's a very strange problem, I searched a lot but couldn't find a solution.

Hi Guys,

In Lenovo, there is a program called Catalyst Control Center that deals with graphics, video and games, I added Firefox to its list of the applications that need graphic acceleration by mistake. I removed Firefox from the form a sub category called "Switchable Graphics" and everything came back normal.