Unbelievable Strange Problem

I have a ND-3550A and when i connect it to the computer start up and everthing on the computer slows down dramatically. I try jumpers, ribbon change etc. http://club.cdfreaks.com/showthread.php?t=163455

Believe it or not what happened:
I tried everthing including firmware update nothing work. Accidently, I discovered that at beginning of the start up or slow system work IF I OPEN THE TRAY OF MY ND-3550A everything works perfect.

How and Why, How I am going to fix it I dont know