Did you try the first change?
To create a stored procedure select tools-add procedure... from the vb menu. Enter a name and select Sub and Private. Then cut and paste everything from the 'On error..' statement to the last 'end if' before the end sub line. Paste it between the two lines of your new stored procedure. Last step go back to the form activate and type in the name of the new procedure you just created. It should be the onlt line that you see.
You should end up with something like you see below.
Private Sub Form_Activate()
ClassNumber
End Sub
Private Sub ClassNumber()
On Error GoTo ErrorHandler
ContinueHere:
prompt$ = "Please enter class number."
Do
SearchStr$ = InputBox(prompt$, "CLASS NUMBER"

datClassEval.Recordset.Index = "PrimaryKey"
datClassEval.Recordset.Seek "=", SearchStr$
Loop While datClassEval.Recordset.NoMatch
txtLocator.Text = datClassEval.Recordset![LocNumber]
txtName.Text = datClassEval.Recordset![CLASS_NAME]
txtTrainer.Text = datClassEval.Recordset![REGISTRAR_INSTRUCTOR]
txtDate.Text = datClassEval.Recordset![Date]
txtHours.Text = datClassEval.Recordset![CLASS_HOURS]
ErrorHandler:
If Error = 3421 Then
MsgBox "Please check", vbCritical
Resume ContinueHere
End If
End Sub
Thanks and Good Luck!
zemp