What was the name of this account?
It may be normal. For example, if your system downloaded and installed Microsoft's .net framework, (required for enhanced web browsing amongst other things), you will see a new account added.
May I add: You only have one Admin capable account it seems. How will you access the system as an Administrator if that account fails for some reason?
This is what we suggest, (in fact, recommend):
1] XP arrives with a "System Administrator" account already set up. It has to, otherwise we would not be able to log in as an admin.
2] Create your own Admin capable account immediately. As soon as you do that, the inbuilt System Administrator account disappears from any login screen, although it is still there and still available in Safe Mode.
3] Then create a "Second Admin capable account". If your first account becomes inaccessible for any reason, you still have the ability to login as an admin using the 2nd account.
dear experts and otherwise wise men,
My PC has winxp professional for years with only one user - me, and lately there popped up an user account from who knows where.
In order to get rid of the impudent encrocher it was deleted via Control Panel>User Accounts and after a few days of absence it popped up again. This time it was deleted via System Tools just to come up againg with its password and things.
Of course I can live with it and my question is from pure curiosity - how does that come about that self-establishing user account?