I have a pc with a Gigabyte EP45T-UD3LR(Socket 775)motherboard which has 4 RAM slots and is supposed to be capable of 16GB total RAM. I have 8GB now-2 sticks of 4GB DDR3L-1600 UDIMM 1.35 CL 11. I ordered 2 more more sticks of same, down to the brand-Crucial. Installed the RAM and computer powers up but doesn't boot, shuts down then tries again...repeats....Help?Is the RAM on the MBoards QVL list ? ? I'm going off a scan done by Crucial that says the RAM is compatible. And it does work with 2 4GB sticks, but with 2 more of same, for total of 16, is doesnt.What RAM is in there and what RAM did you buy ? ?It had 2 - Crucial 4GB DDR3L-1600 for total of 8GB. I bought 2 more of same exact THING. I've been on Gigabytes site and Gigabytes owners manual and it says the vendor(Crucial)is on the QVL and that max memory is 16GB. The motherboard is GA-EP45T-UD3LR with 4 memory slots. Works with 2 but not 4...?Rule of thumb is to never mix ram. Even though you purchased 2 identical  sticks of the same ram you had. You should purchase 4 sticks at the same time. All 4 should be from the batch. Yeah it sounds stupid.
Possibly bad sticks or the timings could be different ?
BSOD victim because of ram.The GA-EP45T-UD3LR comes with Intel's "Flex Memory technology," which allows the motherboard to react gracefully if MULTIPLE RAM types are installed. So this motherboard should not freak out because of DIFFERENCES in RAM, or at a minimum, the Intel Flex should provide you with a message at POST about it.

If I were you I would try removing the old RAM, and installing the new RAM in the same slots. Does the computer boot normally? If so, the new RAM sticks are probably OK.

You also might want to GO into the BIOS and load the fail-safe defaults for your DRAM configuration as on page 37 of the manual http://download.gigabyte.asia/FileList/Manual/mb_manual_ga-ep45t-ud3lr_v1.1_e.pdf

Also - if you're getting beeping at the failed boots, check the beep codes on page 98 of the manual, that might shed some light.