MSI 790x GD70 cmos checksum bad

I just recently started having very strange computer problems

Specs
MSI 790x GD70
ATI Radeon 4890 AMD
Phenom II X4 955 quad core
4g ddr3

I was away from my computer for two months and when I came back I suddenly started having cmos checksum bad errors every time I booted. I would load the default bios values and continue and everything would be fine. Lately, after I go through the cmos error prompt windows will begin to boot and freeze, or will freeze on a black screen which results in having to do a manual restart.

Sometimes when windows does boot I can do normal activities (Web, and games) but after 10 or so minutes the screen will look as if it is tearing and it will freeze. It looks as if the colors on the screen are smeared in a horizontal direction and the whole machine freezes. Usually I have to manually start my PC 2 or 3 times before windows loads and I can use it with no problems. I am actually using it right now to write this post.

Any help or suggestions would be greatly appreciated because I badly need this PC to do university work and research. Thanks in advance for any advice!