Sorry, here are crash details:

AdapterDeviceID: 0df2 AdapterVendorID: 10de Add-ons: LogMeInClient@logmein.com:1.0.0.664,support@lastpass.com:1.75.0,{37fa1426-b82d-11db-8314-0800200c9a66}:2.8,amznUWL2@amazon.com:1.7,canitbecheaper@trafficbroker.co.uk:3.3.4,{972ce4c6-7e08-4474-a285-3208198ce6fd}:7.0.1 AvailableVirtualMemory: 3859050496 BuildID: 20110928134238 CrashTime: 1320410357 EMCheckCompatibility: true FramePoisonBase: 00000000f0de0000 FramePoisonSize: 65536 InstallTime: 1317354595 Notes: AdapterVendorID: 10de, AdapterDeviceID: 0df2, AdapterDriverVersion: 8.17.12.5939 D2D? D2D+ DWrite? DWrite+ D3D10 Layers? D3D10 Layers+

ProductName: Firefox ReleaseChannel: release SecondsSinceLastCrash: 555 StartupTime: 1320410352 SystemMemoryUsePercentage: 35 Theme: classic/1.0 Throttleable: 1 TotalVirtualMemory: 4294836224 URL: http://www.pugauthority.com/ Vendor: Mozilla Version: 7.0.1 Winsock_LSP: MSAFD Tcpip [TCP/IP] : 2 : 1 : %SystemRoot%\system32\mswsock.dll

MSAFD Tcpip [UDP/IP] : 2 : 2 :  
MSAFD Tcpip [RAW/IP] : 2 : 3 : %SystemRoot%\system32\mswsock.dll 
MSAFD Tcpip [TCP/IPv6] : 2 : 1 :  
MSAFD Tcpip [UDP/IPv6] : 2 : 2 : %SystemRoot%\system32\mswsock.dll 
MSAFD Tcpip [RAW/IPv6] : 2 : 3 :  
RSVP TCPv6 Service Provider : 2 : 1 : %SystemRoot%\system32\mswsock.dll 
RSVP TCP Service Provider : 2 : 1 :  
RSVP UDPv6 Service Provider : 2 : 2 : %SystemRoot%\system32\mswsock.dll 
RSVP UDP Service Provider : 2 : 2 : 

This report also contains technical information about the state of the application when it crashed.

When you send Mozilla a crash report it just puts it in a giant database. We have no way of looking it up without the Report ID. I have no idea what is wrong without looking up the crash report. Please get the Report ID of your latest crash report.
See https://support.mozilla.com/en-US/kb/Firefox%20crashes

Crash ID is in original post: bp-c30e93c1-f8c9-475f-8940-6f3e92111104

I believe I've figured it out though, by looking at other threads. Seems to have been a Trusteer Rapport issue.

Sorry, I overlooked your crashID. I was working on several crashes at the same time. That was a bad idea. If you have Trusteer Rapport you can try to stop that. Then the crashing should stop.

Your crashreport is:
https://crash-stats.mozilla.com/report/index/bp-c30e93c1-f8c9-475f-8940-6f3e92111104
Firefox 7.0.1 Crash Report [@ _purecall | nsXPTCStubBase::QueryInterface(nsID const&, void**) ]

Firefox 7 seems to work Ok if I stop Trusteer Rapport. Unfortunately, I need this software to operate e-banking. Do you think you´ll be able to provide a definitive solution soon? Thanks.

Dilbert66,

You can vote for the related bug (699776 NEW crash in nsXPTCStubBase::QueryInterface involving RapportTanzan7.dll in the stack) which will keep you updated by e-mail of the progress of the bug fix .... or simply bookmark the bug report and check back periodically. You can also contact Trusteer Support to see when a fixed version of their Rapport product will be available.

@Dilbert66
According to the user in question 892517 Trusteer is aware of the problem and working on a fix. I think they will try to send you an update as soon as possible, just like they did with the previous series of crashes. But you should really ask that to their helpdesk. People that make programs that should work with Firefox are responsible themselves of making sure that it actually works with Firefox.
http://www.trusteer.com/support/