Startup question - computer showing me some kind of BIOs?

[messagetyper]

Afrer not using the computer for a week, my pc suddenly powers up by it's own each time I open the slot for the CPU on my extension meaning I don't have to press the power button on the CPU which is weird, and instead of hearing just one beep, my CPU makes 2 more beeps after the first one.

After that this weird BIOs would show up(as shown on the attachment) and when my computer finally starts up, it would suddenly flash duplicates of my home screen forcing me to restart the entire thing. Any solutions?

 

[Ztruker]

CMOS checksum error means the CMOS battery in your computer needs to be replaced.

It's a CR2032 and is about the size of a quarter. They usually coast around $2.

Power off the computer, disconnect the power cord then open the case and look for the battery.

This shows how to replace it on an Emachine. Yours may not be the same but should be similar:
How do I remove the battery on my emachine desktop?