Excel 2007 crashes upon startup

[pf1]

Hi,
My Excel 2007 crashes upon startup and displays the following erro
signature:

Problem signature:
Problem Event Name: APPCRASH
Application Name: EXCEL.EXE
Application Version: 12.0.6300.5000
Application Timestamp: 47607042
Fault Module Name: mso.dll
Fault Module Version: 12.0.6213.1000
Fault Module Timestamp: 46eafebf
Exception Code: c0000005
Exception Offset: 00928fcd
OS Version: 6.0.6000.2.0.0.768.2
Locale ID: 1033

Additional information about the problem:
LCID: 1033
Brand: Office12Crash
skulcid: 1033

Does anyone please know how to fix it? I am running on Vista.

Thank