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Mix-Matching RAM has it's risks and the solution might be to purchase a Fully-Matched Set. I would use BIOS version 2003 or 2101 and confirm the following are all as shown below.
As a test, install only the 2x2GB set and make certain the RAM is properly seated and locked-in. Next in the BIOS press F5 (Load Defaults), change other required settings i.e. SATA-> AHCI (if used, etc) and F10 (Save & Exit):
CPU: | blank | 2GB | blank | 2GB |
Assuming you have 4GB then add the 2x1GB:
CPU: | 1GB | 2GB | 1GB | 2GB |
IF that fails then please post a link to BOTH sets of RAM.
An important indicator is the amount of 'Hardware Reserved' - it shouldn't be >30MB~50MB if there's no onboard iGPU (video):