Ram Issue on "my super pc" - rebuild or buy new ram?

I built this system about 2 years ago...

For the last year I been having reboot issues and I gave up trying to troubleshoot and took it in. They ended up pulling 3 sticks of ram (crucial DDR3) out of the system.

I had one stick left and that failed. Now the system is dead for obvious reason.

So, the question is do I rebuild the system or buy more ram?
Am I likely to kill the new ram if it's something else like the motherboard?
I never went into the bios to change the speed; I read it somewhere here that it should be set to 2.1 ?? I didn't do that an I need to look into that more.
Anyways.

I just don't want to keep dumping money into a system that's going to keep eating money...

Any suggestions? Thanks

Also, since I have Crucial Memory I believe it has a lifetime warranty, would they guarantee this memory? Might they replace all of it or would I be better trying to have them replace one stick?

The first thing is to determine the proper voltage for the ram. Check the crucial website, and find out what it should be set at. Then go into the BIOS and set it accordingly.

I've built a couple PCs and this is the first time I've heard of this. I usually just pop the memory in and reboot.

Could that ruin the memory?

Set the voltage to match the ram, then put the ram back in one stick at a time and see what happens.