MMC Hangs

I have a WinNT4.0 server, sp6a, using WinNT 4.0 option pack. When I open the Internet Service Manager under IIS 4, MMC v1.0 opens perfect the first time. If I close it, and try to open it again later, it hangs. Just the splash screen and hour glass come up. It doesn’t even show in task manager. If I logout, I get a message asking if I want to save the console. The only way I can get back into it is by restarting the machine. I’ve reinstalled sp6a several times to no avail. All help appreciated.