Started Firefox this morning and found that it just wouldn't connect to certain sites, despite there being no problem with my internet connection. I resolved this by clearing the cache but now I'm having a problem whereby Firefox crashes randomly when I try and switch between tabs. Only thing I can do close it and start again, having to always tell it to restore tabs manually, but unfortunately it doesn't generate a crash report. Seems to happen more often on sites that are playing flash videos, but not always.

The problem doesn't seem to occur in safe mode but I've tried disabling all add ons in regular mode and it still crashes so it doesn't seem like the problem lies there. I've run a full malware and virus check which found nothing, Chrome and IE have no issues on the same sites. Any ideas would be appreciated.