Exact message: Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system This happened when I first booted up the computer (so I hadn't been running Firefox anyway). I already tried: -restarting and shutting off. This does not help. However, the system felt the need to run an error check on one of the restarts, which turned up nothing. This might indicate something. -Opening task manager. firefox.exe does not appear in the processes list. -Using the help file. None of it seems to help since the profiles folder is empty. I can't run profile manager either. -uninstalling and reinstalling. I STILL GET THE SAME ERROR. Furthermore, the profiles folder is still empty! I am currently running a virus scan, so far nothing. IE seems to be unaffected. EDIT: Latest version of Malwarebytes has turned up no threats.