If you upgraded from Windows NT, the profiles are in the same location, %SystemRoot%\Profiles.

If you have a new installation, or upgraded from W9x, the User Profiles is created in %SystemDrive%\Documents and Settings\xxxNAMExxx, which can be addressed as %USERPROFILE%.

The xxxNAMExxx is based upon the User ID, and may be suffixed.

If JohnDoe (JohnDoe@DomainName.com) logs on, the %USERPROFILE% created would normally be
%SystemDrive%\Documents and Settings\JohnDoe.

If another JohnDoe logs on, as in a local account, or from a different domain, the %USERPROFILE% created could be
%SystemDrive%\Documents and Settings\JohnDoe.LocalComputer or
%SystemDrive%\Documents and Settings\JohnDoe.OtherDomain respectively.

NOTE: The system knows that the SID is different.

If a user logs on again, after the Domain was recreated (clean install), the %USERPROFILE% could be
%SystemDrive%\Documents and Settings\JohnDoe.000 or
%SystemDrive%\Documents and Settings\JohnDoe.domain.000 or
%SystemDrive%\Documents and Settings\JohnDoe.domain.001.

During my 2nd PDC and WorkStations disaster/rebuild, I managed to have 3 different permuations of Jerry on my hard drive.

NOTE: My 3rd rebuild worked like a charm.