There are a few different ways.  Here are some things to try:

1)  When you turn on your Windows computer and log in (by pressing CTRL-ALT-Del on Windows XP, 2000, NT; on Windows 95 and 98 the login screen appears automatically after rebooting), the name that appears in the USER NAME box is generally your user name.

2)   If you access resources stored on a server (i.e. you have drive letters in addition to A:, C:, D:, E:), you may have a drive mapped to your home directory and may look like this:  BlowJo$ on Porsche (H:).  The characters to the left of the dollar sign ($) are your user name.

3)   You can use your email name to find out.  Open a new email message, and in the TO: field, either search for your own name in the Address Book, or simply type your name, last name first, as in Blow Joe.  As soon as Outlook recognizes the name as being part of its Address Book, it will be underlined.  Click once on your now underlined named.  Then do a right mouse click and select Properties.  A window will open named Blow Joe Properties.  The General tab should be at the forefront.  If it’s not, just select General.  On the right side of this window, second line down, is a field called Alias.  It contains your user name.

4)   If you are using a Macintosh, Unix, or for any other reason can’t find your user name, please call your LAN Administrator or the IS Help Desk at (303) 724-0495.