Try using regedit. The relavant key is HKLM\Software\Stardock\Drengin.net\GC2
The string values in that key should be:
"Exe", the executable that is run when choosing run application is SDCentral
"Path", the path to the installed game directory
"Type", must be "Beta" or "Production"
"Updated", when have you last updated the game. Format is M/D/YY
"Version", the currently installed version.
Only Path is truly important, I think. "Version" must be less than current version to get the update option. "Exe" might be checked too.
For Darkavatar it is "DarkAvatar" instead of GC2.
Only ComponentManager and Object Desktop is there. Drengin.net is not present.
By HKLM I think you mean HK_Local_machine.
My game runs fine. I just want to update via Stardock Central. Help please.