First of all, Firefox 1.5 is NOT SUPPORTED and has been discontinued and is slow, insecure, heavy and lacks features. Please update to the newest version to have the fastest and most secure experience possible. It's free. The following advice is for Firefox 3.6. ''''''''''''''''''''''''''''''''''''__ If you can't delete the search engines that come by default, do this: - type about:support in the address bar; - click "Open Containing Folder" near where it says "Profile Directory"; - your profile directory will appear (this is the folder you need to backup if you want to backup your profile, I don't know, if you want to format your computer or something, so you don't loose your stuff); - open the folder "searchplugins"; - delete the xml files you don't want. Each xml file corresponds to one of the search engines you have installed. You can store them somewhere else if you want to back them um, just not inside the searchplugins folder (a subfolder is fine); - restart your browser and the ones you deleted will be gone. Hope it helps.

See http://forums.mozillazine.org/viewtopic.php?f=38&t=627084&p=5069645#p5069645