If Len(Me.txtYourInfo) < 8 Then MsgBox("You need at least 8 letters.",,"Invalid Entry")
For i = 1 To Len(Me.txtYourInfo)
Select Case Mid(Me.txtYourInfo,i,1)
Case B, H, X, D, T
Case Else
MsgBox("You must have only a B,H,X,D or T as letters.",,"Invalid Entry")
End Select
Next i