CHANGE WINDOWS DURING WRITING AFTER 10 SECOND OF WRITING

THE POINTER OF MOUSE  AFTER 10 [s]  MOVES IN ANOTHER WINDOW OR STOPPED IT DURING THE WRITNG AND THE PROBLEM IS I LOST CHARACTER DURING THE WRITING. IT IS A PROBLEM FOR DIGIT THE PASSWORD OR DOCUMENT. 

I clear the register, I change the mouse and the keyboard but nothing to do. 

During the start up I feel 4 short beep but I don't know what to do. 

Thanks for help