2003 server: MMC cannot open the file c:\WINDOWS\system32\dsa.msc.

Hi,
I cannot run "Active Directory users and computers" from "Administrative Tools" on 2003 server. It gives me the error message:
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MMC cannot open the file c:\WINDOWS\system32\dsa.msc.

This may be because the file does not exist, is not an MMC console, or was created by a later version of MMC. This may also be because you do not have sufficient access rights to the file.
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In the morning, I found my server was slow. I logged on to it, because USB back up failed, it showed up write delay errors. I tried to run "Active Directory users and computers" to change an user's password, it takes a long time to load it. Then I could not close it. Then I tried to reboot the server. After rebooting, I could not access to it anymore. But I can use MMC to add it manually.

Thanks,
Lijunguo

Solution: 2003 server: MMC cannot open the file c:\WINDOWS\system32\dsa.msc.

IS the dsa.msc file present at the location.
if not then you could open the ADUC snap-in in MMC and save it as DSA.msc under C;\windows\system32. and it should work.