I decided to try recovering SCSM 2010 after a failed Self Service Portal install (self-inflicted fail when I didn’t use the right security account for the portal install).
FYI, if you install the Self Service Portal and don’t use the same local admin account running the Service Manager service, you can’t go into IIS and fix this. Make sure you use the right accounts.
After uninstalling SM 2010, I encountered a “ _CreateMOMRegKey” error during the reinstall. I posted the problem in MS System Center forum and the good folks at Microsoft directed me to manually delete these two keys:
HKLM\Software\Microsoft\Microsoft Operations Manager
After doing this, I still received a “:_CreateMOMRegKey” error when reinstalling. Searching around I found that you needed to restore your previously backed-up encryption key (per the SM Disaster Recovery guide) . Using the <Your Set Up Directory>\amd64\Tools\SecureStorageBackup\SecureStorageBackup.exe and reinstalling the latest encryption key backup, the reinstall of both SM Service Manager and the Self Service Portal finished with no problems.
Hope this helps.