I would go along these lines. A 5x5 grid sounds like a good use of a TableLyoutPanel. You'd place your 25 Labels in the cells of the table and then do something like this:
VB Code:
  1. Dim myRandom As New Random
  2.  
  3. For Each lbl As Label in myTableLayoutPanel.Controls
  4.     If myRandom.Next(0, 10) = 0 Then
  5.         'Kill the Label.
  6.         lbl.Dispose()
  7.         myTableLayoutPanel.Controls.Remove(lbl)
  8.     End If
  9. Next lbl