This character will emerge on desktop always you done alteration to Windows Address Book which is exploited by Outlook Express. It is part of a security patch for Outlook Express for an error which could allow an attacker to run malicious code of alternative on a user's machine. Sadly there is an error for error repair also.

When you do alters in Windows Address Book file, Windows will make a backup of this file. The patch renames endorsement file to ~ and saves it in directory where you introduce Outlook Express. Many people introduce Outlook Express from a shortcut on desktop, so endorsement file gets located there.

You can delete this file but it is suggested that you back it up first as it is a support of Windows Address Book. I would rename it to somewhat like addressbackup.wab so it is simple to identify it. Give .wab extension on it to attach file with address book.