Your crashreport:
https://crash-stats.mozilla.com/report/index/bp-9ec5c8ad-623c-4565-a964-10af62111104
Firefox 7.0.1 Crash Report [@ _purecall | nsXPTCStubBase::QueryInterface(nsID const&, void**) ]
This is caused by Trusteer Rapport. Try to disable it and see if that stops the crashing.
You can stop Rapport using Start Menu > Programs > Trusteer Rapport > Stop Rapport
You can ask their helpdesk when an updated version of their product will be made available or, if you don't need this software, uninstall it.
http://www.trusteer.com/support/en/report-problem
According to the user in question 892517 Trusteer is aware of the problem and working on a fix.
See also Bug 699776 - crash in nsXPTCStubBase::QueryInterface involving RapportTanzan7.dll in the stack.

Disabling Rapport did in fact fix the problem. Will update "blogs" to let other users of Rapport know. Thanks for fast repsonse.

I am having the same issue, but do not have Rapport

All I can say is that is probably another plug-in as there appears to be lots of other people with the same crash report. Cut and paste the above crash report http and check the comments.