Admins can change an original username to a random username. I saw some cases like this with privacy issues like you mentioned.
But i guess this will be not count in this case for an Account that has only 4 Posts with this Thread here included.
There are also not really anything important on the other posts that have some Information that it should be deleted or the Account name changed.
Even the Account is an old one i would say that the OP should just change the password its hard to remember or the Admins lock that Account.
As others have already written a PM to theymos for delete the Account is the best way.