Firefox not running after latest update, error AppHangB1

Standard method for fixing what may well have been a faulty download or install, a quote from MozillaZine:

Close all applications and reboot the computer.
Delete any downloaded or partially downloaded installer files.
Clear the browser cache (of whatever browser you are using to download FF) and the Windows Temp directory.
Shutdown any anti-virus software you are running.
Download a new copy of the full installer from www.mozilla.com
Delete the directory C:\Program Files\Mozilla Firefox
Run the installer.
Restart the anti-virus program.

Download/install failures are not common (whatever "common" means mathmatically,) but they do happen, and the above instructions most often fix the malady.

Please ignore comments such as Firefox 15 may have a bug; were that true, there would be many complaints on such forums as MozillaZine to that effect, complaints that don't exist as of a few minutes ago. Rather than flail around, please try the proven and simple fix.

Will that work? Obviously I don't know; I only know that it has been demonstrated to be of use and, thus, likely to be worth trying.

Not Myself said:

Standard method for fixing what may well have been a faulty download or install, a quote from MozillaZine:

Close all applications and reboot the computer.
Delete any downloaded or partially downloaded installer files.
Clear the browser cache (of whatever browser you are using to download FF) and the Windows Temp directory.
Shutdown any anti-virus software you are running.
Download a new copy of the full installer from www.mozilla.com
Delete the directory C:\Program Files\Mozilla Firefox
Run the installer.
Restart the anti-virus program.

Download/install failures are not common (whatever "common" means mathmatically,) but they do happen, and the above instructions most often fix the malady.

Please ignore comments such as Firefox 15 may have a bug; were that true, there would be many complaints on such forums as MozillaZine to that effect, complaints that don't exist as of a few minutes ago. Rather than flail around, please try the proven and simple fix.

Will that work? Obviously I don't know; I only know that it has been demonstrated to be of use and, thus, likely to be worth trying.

I am pretty sure the issue was caused by me. I probably fück*d up my Windows by uninstalling Microsoft Security Essentials using Your Uninstaller Pro. It probably messed up my windows registry.

Layback Bear said:

From the cmd prompt run sfc /scannow. It can't hurt but might help. Run it 3 time and boot after each.

Folks at PaleMoon.org reported some issues to the programmer/optimizer, Moonchild, and he addressed them in one of his posts at the forum.

In particular, the gecko 15 engine underneath Firefox 15 introduced some changes that played havoc with heavyweight custom themes and add-on's that haven't kept up with Mozilla's march towards "progress".

Options are: run in safe mode, create a new profile or disable all add-on's for the current profile and work with one add-on at a time to isolate the culprit.