Firefox 11 is quite old. Try updating to Firefox 14.0.1, which does have alot of fixed crashes since then. You can download it from www.getfirefox.com.

If that doesn't help, let me know.

Cheers for the reply. I've uninstalled Firefox, rebooted, installed 14.0.1 without any personal data and it opens ok! However when I close it normally and try to restart it, it crashes without opening, will not reopen in safemode, says it has produced a crash report, but it's not in the folder and it will not reopen again!? Any ideas? Thanks Dave