When I try to start firefox, using a shortcut or Start>>Run>>firefox, nothing appears to happen at all. Checking the Windows Task Manager, the Applications tabs shows nothing, but the Processes tab shows firefox.exe running. (I always apply the Task Manager's End Process funtion to this instance of firefox.exe before trying firefox again.) I have tried reinstalling Firefox and using System Restore to and earlier date. Neither approach has made any difference. When I try to start firefox using Start>>Run>>firefox -ProfileManager, I get a dialog offering to send a crash report to Mozilla. When I follow the instructions to obtain the crash report, the report says: Firefox 3.6.6 Crash Report [@ nsWindowWatcher::OpenWindowJSInternal(nsIDOMWindow*, char const*, char const*, char const*, int, nsIArray*, int, nsIDOMWindow**) ] When I follow the Search Mozilla Support for Help link, just one item comes up. In it, the only recommendation that I delete a file called compreg.dat. Unfortunately, this file is already missing from my Profiles directory, and indeed is nowhere on my computer. Mozilla has general advice on "crashing at startup", but none of it has been useful. The crash happens in Firefox safe mode. There does not appear to be any viruses (like Backdoor.Urlbot.C). What else can I try? Thank you == Crash ID(s) == 11b88507-b103-47ef-a684-2cba72100710 == User Agent == Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)