Desert Eagle

My friend’s computer is broken
It can’t start up without any sound.
I had to checked all parts of it.
Harddisk,Display Card,PC power etc.
Replace all parts as my parts,except mainboard.
The mainboard is Epox 8RDA3
It was the same later.
Why was there no sound?
It should be some sounds when self-check.
I had to check all line again.
Suddenly I found the line of horn in PC case was broken.
That is why I can’t hear the self check sound.
Connected the line
Restart PC
It sounded
The sound showed that the problem is memory!
It is Kingston memory,but why it is broken soon?