Good news, I swapped the sticks around and re-seated. (One of them was not in all the way, whoops!)
8GB (both sticks) are back in use and the slots have been cleaned out, I really appreciate all the help!
The one time I did test the RAM (with the first Memtest I used) it caught a ton of errors, found a forum post that was the exact amount that I had (like 65000+ or something along those lines), they cleaned out the slots with an alcohol swab, and it wound up working.
I'll test the RAM again later this week to check if they are good, but I'm thinking it was just that dust was packing it up!
If anything happens I will post it up here or create a new thread, I'm pretty sure the dust was the problem though, we shall see. I'll let the PC run for a few days.