- On my Geforce xx the graphics has not cleaned

I don't understand why, I have tried on different computers
with geforce card but the problem is common to all!!!

- If I change the Event Timer the program doesn't respond

On slower computers (<1000mhz) the event timer must be set to 100 or more.

- I can't see the demos

Probably your computer is too slow.
The computer has to be with a processor than at least 1Ghz  
with a good graphic card (>Geforce 2 mx).