Arduino program problem


I have a problem with the Arduino program. It started about a week ago for no apparent reason…

The problem is that the program keeps over laying the program with stills of itself… to show what i mean here is a picture:


If anyone can help me solve this problem it would be so appreciated!

Its doing my nut in currently. i have to shut Arduino down every time it happens and reload the program. Currently every 30 seconds.

Many thanks,