Hi - using ASP/Access/Vbscript

Want to use a alternative of the DW check if username exist behaviour.

I have a insert record form on my page. On insert the username is checked
against a database using the DW behaviour.
If username exist- then the insert record is approved and record inserted.
If username not exist - then the insert record is fail, and user is redirected
to a failure page.

Possible? Any suggestions on how to do this?

Thanx!

Bj?rn-Tore