See: * http://kb.mozillazine.org/Firefox_crashes * https://support.mozilla.com/kb/Firefox+crashes

Profile: C:\Documents and Settings\<user>\Application Data\Mozilla\Firefox\Profiles\<profile>\
Cache: C:\Documents and Settings\<user>\Local Settings\Application Data\Mozilla\Firefox\Profiles\<profile>\

Try to delete <strike>the startupCache folder</strike> (that is for Firefox 4+) the file compreg.dat in the Firefox Profile Folder and the files XPC.mfl and XUL.mfl in the parent folder of the Cache folder (see the about:caches page for the location of the cache) *http://kb.mozillazine.org/Profile_folder_-_Firefox *Help > Troubleshooting Information > Profile Directory: Open Containing Folder Profile: C:\Documents and Settings\&lt;user&gt;\Application Data\Mozilla\Firefox\Profiles\&lt;profile&gt;\ Cache: C:\Documents and Settings\&lt;user&gt;\Local Settings\Application Data\Mozilla\Firefox\Profiles\&lt;profile&gt;\ ---- Create a new profile as a test to check if your current profile is causing the problems.<br /> See "Basic Troubleshooting: Make a new profile":<br /> *https://support.mozilla.com/kb/Basic+Troubleshooting#w_8-make-a-new-profile<br /> There may be extensions and plugins installed by default in a new profile, so check that in "Tools > Add-ons > Extensions & Plugins" in case there are still problems.<br /> If that new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.<br /> See:<br /> *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox<br />

also i suggest you to upgrade your Firfox 3.6 to Firefox 7 where we fix lot of crash n freezes * getfirefox.com