Hi Miitch
and Welcome to the Forum
To check for compatibility issues we need to know what Intel CPU your using?
Failure to boot can happen if your combining/mixing RAM kits due to minute variations in Latency.
Manufacturers warn of this and it's the reason Dimms are binned to ensure they are matched and compatible then put into a single kit.
Many think that they should be compatible if they have the same specs however NOT SO.
Best is to have a single kit the size you need that are supported by both CPU and MB and listed on the MB QVL. That way you know they are tested and known to work.
If it continues and you lack Overclocking experience then save yourself the frustration, return what you have and get a single kit (2x8).
If they are a single kit then manually set the XMP profile in Bios for a simple easy Overclock. You may have to adjust Dram Voltage or your Primary Timings to suit. Your SPD settings can be found in CPUz should you manage to boot into Windows.
It is also best to update your Bios and chipset and just use one Dimm inthe RAM slot meant for single channel mode to test initially.