Userform - Adding Data to Existing Rows

I think this is the problem:

Private Sub cmbFind_Click()
Dim lastrow
Dim myContractNumber As String
lastrow = Sheets("Sheet1").Range("A" & Rows.Count).End(xlUp).Row
myContractNumber = txtContractNumber.Text
For currentrow = 2 To lastrow
If Cells(currentrow, 1).Text = myContractNumber Then

txtContractNumber.Text = Cells(currentrow, 1).Text
txtClient.Text = Cells(currentrow, 4).Text

End If
Next currentrow
txtContractNumber.SetFocus
End Sub

You loop through looking for a match with the contract number and, when you get one, you update the client name. However, you then continue to loop through the data to the lastrow ... hence the currentrow will always equal the lastrow. I think you just need to add an Exit Sub when you find the client you are looking for.

Private Sub cmbFind_Click()
Dim lastrow
Dim myContractNumber As String
lastrow = Sheets("Sheet1").Range("A" & Rows.Count).End(xlUp).Row
myContractNumber = txtContractNumber.Text
For currentrow = 2 To lastrow
     If Cells(currentrow, 1).Text = myContractNumber Then

          txtContractNumber.Text = Cells(currentrow, 1).Text
          txtClient.Text = Cells(currentrow, 4).Text
          Exit Sub

     End If
Next currentrow
txtContractNumber.SetFocus
End Sub

Regards, TMS