When it first starts to boot, you should get a brief screen that tells you to hold down the Del key to go into the BIOS... There, you’ll find settings that deal with RAM if there are any options.

You said Windows 10, but you didn’t say whether it’s 32 or 64 bit version. Right click on the icon in the lower left corner and select control panel if that’s an option, then select system and it will tell you as well as answer the question I asked about how much USABLE memory (NOT total) is installed.

One thing I have seen in the past is that the memory controller chips don't like working with too many memory banks. So if you have an 8GB chip it might be configured (done by how many chips are on each stick of memory) to give you 8GB by using either 1 or 2 (or 2 or 4) banks of memory. So your chip controllers might work fine if each memory stick of memory is single bank making a total of 4 banks. Adding more banks and the memory chip controller might not be able to operate with 8 banks but can handle 6 banks. In the old days you had to select the right number of banks by purchasing the right type of chips. I have seen 4 memory chip boards work with 2 boards with 2 banks each and 2 boards with single banks each making a total of 6 banks. It is all to do with whether the chip controllers can provide enough drive for the total number of banks. And it is not impossible there is a memory controller chip with weak drivers.
I might be inclined to see if you can find somebody who has 4 x 8GB sticks that are a different manufacturer than yours and see if they work. Of course this is only a partial solution since it probably won't be the memory sticks themselves at fault. Or try 2 x 16GB sticks to give you the 32GB as was mentioned above.

Hi all,
I have an AsROCK 970 extreme motherboard, with an AMD processor that can take up to 32 gb of 1866mhz ram. I can use 3 of the 8 gb sticks, in any combination of the ram slots, as long as one slot is left open, it works fine. When I put a 4th in the final slot, the screen stays black and I can't hear anything other than the fans starting up. It has an SSD and an HDD, and I can usually hear the HDD.

I sent the 4th stick to the manufacturer and got it replaced, even though they said it tested fine. Tried it again, and the same thing. I would have thought maybe it is the motherboard, but since it seems happy as long as one of the 4 slots is open, and it doesn't matter which slot. It seems to be something else? I know nothing about bios and stuff like that, but am open to any suggestions. Maybe something in the bios is configured wrong?

I've never heard of anyone trying, or actually using just 3 slots, but is there an issue with slowing down, or anything with working in that configuration? I guess 24 gig is better than the 8 I started with.

Thanks in advance. This is my main editing computer, and I just want it working at peak performance. (have several projects coming due)

A number of motherboards have an led display on them that provides an error code rather than the old fashioned beeps. Not familiar with yours to know if that's applicable.

Running memtest uses a form of DOS so you eliminate windows problems. It takes a long time to run one complete pass, but it will identify problems.

You might also try an audit program, such as speccy from Piriform, to see what your memory looks like to the OS (such as timing, slots used, and a whole bunch of other stuff). Makes it easy to see if all sticks are the same. Free version is fine, but given your system won't boot, you'll have to swap sticks around.