Windows 7 - WMC has stopped working after performing an upgrade repair

A few weeks ago I was having a problem trying to install SP1. After trying a number of suggestions and not wanting to prolong this problem I followed the procedure outlined in "How to Do a Repair Install to Fix Windows 7" This seems to have resolved a number of problems but now I have a new one
Each time I try to start WMC it generates a dialog box with the message "WMC has stopped working" Windows is searching for a solution to the problem. But never finds one.
In reviewing the Event Log, it reports the following;
Event 1001, Windows Error Reporting
Fault bucket 1647451282, type 5
Event Name: CLR20r3
Response: Not available
Cab Id: 0
Problem signature:
P1: ehshell.exe
P2: 6.1.7600.16385
P3: 4a5bd053
P4: mcstore
P5: 6.1.0.0
P6: 4ce7b873
P7: 1a1
P8: 146
P9: System.InvalidOperationException
P10:
Attached files:
C:\Users\vmorrison\AppData\Local\Temp\WERB7AC.tmp.WERInternalMetadata.xml
These files may be available here:
C:\Users\vmorrison\AppData\Local\Microsoft\Windows\WER\ReportArchive\AppCrash_ehshell.exe_1d68bdce62 c123288a841621fd5823e3c247522e_178cc1f9
Analysis symbol:
Rechecking for solution: 0
Report Id: 9e4f3f21-242b-11e1-9e34-00247ef64d3b
Report Status: 0

1) I have run "SFC /verifyonly" and it reports all is well!
2) Under "Turn Windows Features on or off" Have checked, unchecked and checked again "Windows Media Center"
3) under "System Configuration",
General - unchecked "Load startup items"
Services - checked Microsoft services and Disabled all others
Startup - Disabled all
After rebooting I tried to start WMC and got the same results, "WMC has stopped working"
What else can I try short of re-installing upgrade again.

System started out as HP 64bit desktop running Vista Ultimate then upgraded to Window 7 Ultimate.