Should I take the risk or trust Microsoft?
I recently had issues installing windows 7 on my brand new computer, I had to call microsoft to troubleshoot. After going through RAM tests it seems to be that one stick of my Corsair XMS3 DDR3 1600 ( 2 x 2GB ) had been deffective. He had me remove that stick completely and use the other in the first slot to boot. It worked but now I think I should return the defective RAM stick for a new one, but, I am not 100% percent sure If it is defective. I do not want to have to shut down my computer for a day or two after I just finished building it. I asked the tech support guy what would happen if i tried booting with both sticks again and he told me that it could cause errors like blue and black screens upon boot and could possibly cause Windows 7 to not work correctly. Then I asked what would happen if i try it and get errors then take it out and reboot with one stick again and he told me it's not worth taking the risk. Get this, before i had trouble with RAM i looked at system specs and it showed that i had 4GB of RAM. Whats up with that? Does that mean it's not defective? Should i take the risk or listen to Microsoft "Professionals"?
If you have identified a bad stick using memtest86+ then it needs to be replaced. If you try to use it, you may get nasty errors, depending on where the error is, and if windows tries to use that address. It is totally unpredictable.
I think MS might have been a bit misleading if you concluded that permanent damage to your PC could occur. I don't see much chance of that, but anything is possible I suppose. But--- it is a moot point since you do not want to run with a defective stick.
I had a similar situation with my first build some time ago. Since it was my only PC, I was reluctant to shut down waiting for a RMA of the whole kit. I opened an incident with Corsair support. They wanted me to run memtest86+ to verify the problem. Then they offered to replace the kit. They want to replace the whole kit because kits are matched to work together. The sticks used in a kit may get subtle manufacturing changes so mixed sticks may have a problem. If you explain your situation, they will help you. In my case, I sent in the defective stick, and they sent me a new one. It worked fine. An alternative would be to call the seller of the ram kit and ask if a rma exchange is possible. You would buy the replacement kit using a credit card, and your purchase price would be credited back when they recieve the defective kit. Possibly Corsair will do this also.
If nobody will help, buy a second kit, and after you install it, rma the defective kit. Sell it unopened on e-bay, and you will get near full price for it.