The instruction at “0x5a9288f8” referenced memory at “0x5a9288f8”. See if updating System Mechanic fixes the problem or, if don't need the program, consider uninstalling it.
Alternately, do a clean reinstall (use another browser to download the Firefox installer from and, after first removing the Mozilla Firefox installation directory, reinstall Firefox).
   You should now be able to start Firefox.
See Problematic extensions and Firefox crashes#Extensions for more information.
Depending on your browser version and OS, Firefox or Sea Monkey may hang, crash, or simply fail to start because of a problematic plugin.
If possible, visit Mozilla's Plugin Check page with another browser that Plugin Check supports (e.g., Safari or Opera) to help identify installed plugins.
 Update all plugins, uninstall any plugins you no longer need or disable all plugins, to see if that resolves the problem.
       If you use Zone Alarm Force Field (either standalone or as part of Zone Alarm Extreme Security) Firefox may crash at startup or Firefox may fail to start after an update (you may see a message similar to Error: Platform version '9.01' is not compatible with min Version Advanced Settings", and turn off "Enable Virtualization").
If the problem persists, download the Firefox setup file from mozilla.org, remove the "Mozilla Firefox" program folder and then, with Zone Alarm Force Field turned off, reinstall Firefox.      If you see a message similar to Your computer must be restarted to complete a previous upgrade of Firefox after a major update (e.g., from Firefox 3.6 to 8.0) and restarting the computer doesn't help: On Windows, open the Mozilla Firefox installation directory (e.g., C:\Program Files\Mozilla Firefox or, on 64-bit Windows, C:\Program Files (x86)\Mozilla Firefox) and delete the file "moz-upgrade", if found.
 Firefox may fail to start if the Iolo System Mechanic application is installed.