|The window that is supposed to pop up and stay will close immediately if there is a problem with the dcomcnfg program.|
If you go to the cmd prompt before you run it, then run it, you may get an error message we could look up.
Start - Run - type: cmd (click on OK or press Enter)
Type: dcomcnfg (press Enter)
I doubt that you have only one user. You probably have at least two.
The Administrator user only shows up on the logon screen when you load Windows normally if all other users with administrator rights have been deleted or have been assigned limited rights.
All users of XP have administrator rights by default, except the Guest user if someone with administrator rights enables it, which has limited rights, unless someone with administrator rights assigns limited rights to another user, but only one user can be spelled exactly Administrator, and by default that's the built in Administrator user that you can only access when you load Windows in Safe mode.
In XP, using my own user that has administrator rights.....
Note that running dcomcnfg works for me, but I immediately get a window pop up over part of what pops up:
Windows Security Alert
To help protect your computer, Windows Firewall has blocked some features of this program
Do you want to keep blocking this program ?
Keep Blocking - Unblock - Ask me later
Are you by any chance using a third party firewall rather than the Windows firewall ?
If you are, that third party program may be completely blocking dcomcnfg. Try disabling that firewall to see if that cures your problem.