I'm trying to set up my new computer, running WinXP Pro. After installing Mozilla Firefox and Thunderbird, and transferring the Profiles folders from my other computer, I've run into this really annoying problem. When I try to run either Firefox or TB, I get a message box saying that Firefox/TB can't run because another copy is already running but not responding. Close the other one and try again. But I can't find any evidence of the program running. Not in the taskbar, nor in Task Manager. Does anyone know what's going on here, and what I need to do to correct this and be able to use those programs?