Firefox suddenly crashing within seconds of opening

I was told to start a new thread from an earlier thread.

I consider myself a somewhat advanced computer user - I've used firefox for years without issue until today.

When I start firefox, all appears to work well at first. Anywhere between 3-10 seconds after loading the program stops responding and requires an end task - does not matter whether i am trying to access web content, look through the options menu, or just idling. Same issue when running in safe mode. I've tried uninstalling/reinstalling without all of the old addons/cookies etc. I'm running windows 7 ultimate on a high end machine, and have been using firefox without issue for the week or so since I installed it. Internet explorer works perfectly. Kaspersky finds no problems. All other programs on system work great.

This has stumped me - I suppose the next step would be to use some sort of specialty malware removal tool, but I'm frustrated and open to recommendations at this point.