the sleep code stops all code processing in that thread + also stops windows messages being processed.
try this:

vb Code:
  1. Label1.text = "Zero"

  2. label1.invalidate

  3. Sleep (1000)

  4. Label1.text = "One"

  5. label1.invalidate

  6. Sleep (1000)

  7. Label1.text = "Two"

  8. label1.invalidate

  9. Sleep (1000)

  10. ... 

  11. Label1.text = "Five"

  12. label1.invalidate