PC not turning on, Memory Error message

[StudioManager]

PC has been working fine but powered off overnight for the first time in a while (normally just put it to sleep). Won't turn on this morning, motherboard LED is flashing 36-39 error codes:
36 - CPU post-memory initialization. System Management Mode (SMM) initialization
37 - Post-Memory System Agent initialization is started
38 - Post-Memory System Agent initialization (System Agent module specific)
39 - Post-Memory System Agent initialization (System Agent module specific)

Specs below


Any help appreciated, thanks!

 

[TonyCarter]

4 sticks also seems to cause more problems than 2, but I assume this was built for something other than gaming so the lower speed RAM won't matter as much.

 

[ubuysa]

The best way to confirm it's RAM is to remove two sticks. Leave RAM in slots A2 and B2. It it still won't boot then swap sticks, still using A2 and B2. If it won't boot with either pair of sticks removed then it's not RAM.