CMOS Checksum Bad

Hello Guys,
I am trying to trouble shoot my sons computer which I built for him a while ago. He recently tried to add more RAM that he had ordered online. He installed the new RAM and the machine failed to boot up. I pulled the RAM out to examine it to find that it was server RAM. I thought UH OH!. I reinstalled the old RAM and the machine will not boot to BIOS and will give a CMOS Checksum Bad error message. After pressing F2 to continue (this is the only option that will allow it to boot and start windows) windows will run but if I try to restart it will go into a Boot loop or it will blue screen. I cleared the CMOS using jumper method, using battery replacement method and the CMOS switch provided on the motherboard which is the only way to get it to boot back to windows. Can't flash new BIOS because after the flash the "Error: Problem Verifying Flash" comes up. Any ideas on a solution?

Motherboard: XFX nForce 750a SLI Motherboard Nvidia
 
What error codes are the Blue screens showing? And just for clarity sake did you try to set the BIOS settings to their original settings manually?
 
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