For some reason, my Mozilla Firefox browser stopped working. I have both IE and MF installed/available on my PC, but I prefer to use MF. Anyway, when I attempt to open a MF browser window, this message pops up: "The program must allow a previous installation to complete. please restart." Even after I restart the PC, the message still pops up. What can I do to get my MF browser up and running again?

Go to the program installation folder 'C:\Program Files\Mozilla Firefox' and delete the 'xpicleanup.exe' file. Make sure Firefox is not running when you do this. You should be able to start Firefox after that.