Win7 PC repeatedly errors out at bootup to the CMOS bad screen.

I have old CPUs. I swapped out one for a slight upgrade. No matter how many times I cleared CMOS and reset
all the BIOS dates and such, the error would repeat within a couple days. And yes I changed battery for a different one.

Full disclosure: I removed that CPU which was purchased used and put the other old one back in to regain regular use of the PC.

I just wanted to know if there is a traceable error for such a problem. If the CPU was used would overclocking or mining or some other misuse cause a CMOS fail error? It was no big expense I just wanted to have a project to do of swapping out a CPU for what turned out to be not much of an enhancement.

Marked solved. Must be a flaky CPU. As stated I put the original back in from before th swap and things seem
stable with normal startups.