You see the following error "Server Error in '/' Application. Access to the registry key 'Global' is denied" when opening the Web Console in SCOM 2007. This can also sometimes be seen with the word "Error" only.
The console works initially, but after a few hours, days or weeks, the console returns the error.
Running IISRESET will also bring the Console back into a working condition.
Performance monitoring group was missing the Aspnet and the SCOM Action Account - Add these groups/accounts - full control.
Gave Network Service account full permissions on the following two folders: c:\windows\system32\inetsvr and c:\windows\debug\usermode.
Modify the permissions for the following:
C:\Windows\Debug\UserMode - Full Perm - Network Service
C:\Windows\System32\InetSrv - Full Perm - Network Service
HKCR\Installer\Assemblies\Global - Full Perm - Network Service and aspnet - Full Perm