Never-ending Loop

COUNT starts out at 4, which is greater than 0, so the loop body will execute.

' Modified Program
'
LET COUNT = 4            'Statement 1
'
DO WHILE COUNT  > 0      'Statement 2
  PRINT COUNT            'Statement 3
  LET COUNT = COUNT + 1  'Statement 4
LOOP 
END

At the end of the loop body, COUNT is changed to 5. The DO WHILE will let the loop body execute again, and COUNT is changed to 6.

COUNT starts out above 0, and keeps getting larger each time, so the condition:

DO WHILE COUNT  > 0
           ^
           |
           +--- always 4 or larger

will always be true. Actually, there is a problem.