A user's specific information may be corrupted, but other users on the same computer may have no problems. To determine whether this is the case, log on as a new user, or create a new user account, and then test the new logon.
NoteA program may work correctly only when you log on with the default Administrator account. For example, older programs may demonstrate this behavior.
If the default Administrator profile becomes corrupted, reinstall Windows XP to correct this issue.
All user-specific configuration information (which appears in the HKEY_CURRENT_USER registry key) is stored in the Ntuser.dat file in the Documents and Settings\user namefolder