Sage 100

Unable to unistall MAS 200 wkstn. Receive error ""Object registrar is invalid"" I believe it is a corrupt registry entry. Unsure how to proceed. User is local admin.

I take it you looked at this KB article (456579)? Option 1: Install the most recent service pack and updates for Sage MAS 90 or 200. Note: If using third-party software, verify with the software vendors that their product is compatible with the Sage MAS 90 or 200 service updates. Login as the network or local administrator. Run an antispyware scan and a complete antivirus scan. Disable antivirus software before starting the installation process. Map a drive to the folder that contains the ..\Mas90\ folder, for example ..\Acctng\MAS90\. Browse to the ..\Mas90\Wksetup\ folder. Double-click Wksetup.exe, and run the installation. Option 2: Use the CD to run Workstation Setup at the workstation. Option 3: Restart the computer in safe mode. On the Start menu, click Run. Browse to the Wksetup.exe file, and click Open. At the Run window, append NoOSCheck to the end of the installation string (for example, ""M:\MAS90\Wksetup\Wksetup.exe"" NoOSCheck). Click OK, and then run the installation.

Try logging on as the domain admin and running workstation setup. If logging in as another user works, you might need to re-create the users profile.