Managing large text boxes

Hello! I have found while populating a text box with code similar to :

  Dim filename As String
  filename = "c:\large.txt"
  Open filename For Input As #1
  Dim x As Variant
  Do While Not EOF(1)
    Line Input #1, x
    textbox.Text = textbox.Text + x + vbCrLf
  Loop
Close #1

that handling 1000+ lines causes the program to lock up (predicatably) Does anyone has a nice bit of code which allows a routine to read in say 100 lines then detects manages the population of the rest of the file buy scroll or page up/down etc actions?  

Cheers

Stewart Wood