Do you have that problem when running in the Firefox SafeMode?
A troubleshooting mode.
1.You can open the Firefox 4.0 SafeMode by holidng the Shft key when you use the Firefox desktop or Start menu shortcut.
2. Or use the Help menu item, click on Restart with Add-ons Disabled... while Firefox is running.
To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before using the Firefox shortcut to open it again.

If not, see this:
http://support.mozilla.com/en-US/kb/troubleshooting+extensions+and+themes

No in safe mode it does not happen but when i go back to normal mode it happens. I have a new problem now, sometimes the browser works fine and shows tab details but after few hours of use it starts behaving the same way again.

I tried disabling two of my extensions that I thought had the potential to cause this problem (Tab Renamizer and Tab Mix Plus). The problem was fixed upon restart. Then I re-enabled each add-on, one by one, and with both of those re-enabled the problem appears to be fixed, which has be a bit confused. I doubt this is very useful for you but I figured I'd share my experience w/ the same issue.

I started having problems again with this and ended up finding another thread on support.mozilla.com that suggested disabling Tab Renamizer. I did that, restarted, and it worked. I'm pretty convinced that this was my problem. Hope this helps you.

Nope the problem still prevails. I have kinda started accepting the fact that it can't be fixed because I tried everything. I even uninstalled all the add ons still no change. The only way I am able to make my browser work right is reinstalling it every time I use it. I'm getting tired of this. I'm planning to go back to my Firefox 3.6 or just start using chrome instead. Thanks for your help anyways.