RAM stick works on one computer, but not the other

[Rom Hook]

I own two computers but the older one stopped working today. There was nothing on screen when I turned it on so my suspicion fell on an old DDR3, 1333Hz 4 gigs ram stick of unknown manufacturer. I've plugged in a newer DDR3, 1333Hz 8 gigs Kingston memory from my newer PC and my old computer started working like it used to. Then I decided to plug the old 4 gigs ram to my new PC and it worked for some reason. Can someone explain what might be going on?

 

[InvalidError]

Put the original memory back in and see if your no-boot comes back. If it doesn't, then the problem may have been an intermittent connection somewhere that you may have wiggled while swapping DIMMs.

 

[Rom Hook]

Thanks for replying. I've cleaned up the RAM contacts and it works fine now.