Repair (unlock) Windows Installer in Win2K Pro

My Windows Installer has completely stopped working. I have tried doing a Windows 2000 Pro Repair using the Windows 2000 Pro install disk and it did not repair this problem. I feel like it might be some kind of flag set somewhere telling it it is busy! This is what I am calling locked! I have run System Mechanic 6 to also try and fix this. Thanks for any help anyone can provide.

Richard