Try this, I hope this will help you...
As long as I Check this IF condition is Length and Case Sensitive,
* "?" accepts only 1 Character when Matching
* "Adm" is not Equal as "ADM" or "adm".
By Subjecting these limitation my solution is here...
If Ucase(Mid(txtUserName.Text, 1, 5)) Like "ADM_?" Then
Response.Redirect("Address1")
Else
Response.Redirect("Address2")
End IF
Accept Solution if it works...