Windows 7 - Firefox Not responding" ?

That's a start brightsun,

Since I don't use Firefox I won't be much help from here on out, although if you learn how to post screenshots ( The tutorials I linked ) it will definately help others help you.

Here's a list of basic troubleshooting tips for you to look at,

Basic Troubleshooting

derekimo could it mean add on messing up my Firefox ?

Description
Faulting Application Path: D:\Internet\FireFox\plugin-container.exe

Problem signature
Problem Event Name: APPCRASH
Application Name: plugin-container.exe
Application Version: 1.9.2.3855
Application Timestamp: 4c48d590
Fault Module Name: ntdll.dll
Fault Module Version: 6.1.7600.16385
Fault Module Timestamp: 4a5bdadb
Exception Code: c0000005
Exception Offset: 00046b90
OS Version: 6.1.7600.2.0.0.768.3
Locale ID: 1033
Additional Information 1: 0a9e
Additional Information 2: 0a9e372d3b4ad19135b953a78882e789
Additional Information 3: 0a9e
Additional Information 4: 0a9e372d3b4ad19135b953a78882e789

That looks like it might be, here's some simple steps to troubleshoot plug-ins,

Basic Troubleshooting

This indicates that the problem is most likely an external plugin such as a flash, java, pdf plugins, AV plugins are conflicting with FF

Reinstall Firefox
Remove any unnecessary plugins

Plugin-container and out-of-process plugins - MozillaZine Knowledge Base

I was having all sorts of trouble with firefox, and switched to google chrome, but got tired of the tabs at the very top of chrome interfering with the toolbar across the top of Windows 7 and went back to firefox... but the constant not responding, lockups, hesitations from firefox was irritating... so I found this thread... and firefox was about to crash on this very thread topic, then I finally got a message from firefox an error dialog box, saying that it might be the Bing toolbar. I disabled it and have had no problems for the past couple of hours with firefox. Imagine that if it is the case... MS's BING toolbar crashing my firefox... give it a try if you use the BING toolbar. It might alleviate some problems for you.