outlook express

Not much help to be offered,seems as though you have another virus that is not being detected,another option would be to use the Find,Files and Folders to see if their are large files being replicated

The only other option I can think of is that you will have to backup needed files and then wipe the hard drive clean and do a fresh install.

Check for previous post on virus removal in Tech Republic

When user accounts are added to outlook express, new files are created as well as registry entries for those new users. So if you had a virus in the past that created this new user, and you subsequently removed the virus, the "scraps" from those added users were most likely left behind. If you were able to detect the virus the last time this happened, it stands to reason that you could detect one this time as well. Since you don't detect this virus, I doubt if you have it again.

You didn't say if this "user" name is the same as the last time it happened, but I suspect it is. I further suspect that this is somehow caused by the data fragments left behind from your last episode. You could check this by looking for the mailbox files for this unknown user and/or searching the registry for it as well.

I would suggest that you first remove outlook express and all related files - totally. This will involve some registry editing, but it should not create any problems. You could then reinstall outlook express from scratch.

Look at this Microsoft article on TOTALLY removing and reinstalling outlook express. At least this is the first thing I'd try.