2007 Mac Pro MemoryProblem????

I have a 2007 Mac Pro, with 16GB of Ram. The ram in question is from a third party and it is 2GB each stick, i have turned on my mac pro and all the fans spin very very high, it sounds like a jet engine and the fans do not spin down to normal i can use the mac, it is just fans spinning really fast. I opened up the mac and the bottom memory riser is red light the top riser is fine with no red light, i replaced the ram well just one stick and it seem fine, when i booted it back up. But then when i turned on file vault the mac restarted with a blank screen, i have left on for two days and the encryption on the hard drive was never done. I press the power button and the fans were all normal, but then the mac pro froze then the screens went blank, then i press the power button to shut off. Then started it back up now fans are spinning high, so i opened it back up the bottom of the memory riser was red light again, so i took out the bottom riser and turned on the mac pro. And it booted normal no high fans, but now i only have one of the risers in with only 8GB of ram, is the memory riser broken. I tried to put it back in but it wont go in no matter how hard i push the riser in. Should i buy a new replacement riser, with the apple ram or just leave one riser in and just use that, thank you for reading and answering. Stay Classy Yo

Sincerely,

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