Trouble Building PC with Old Biostar Motherboard

--UPDATE--

Got a bit sidetracked... hence the delayed response... however, on my own I managed to discover that my initial problem was apparently aggravated or partially caused by a dead/dying BIOS battery - which after replacing it, the PC was finally able to come up, post, and let me into the BIOS for the first time...

All seemed fine at first, but it is acting weird in some more specific ways now. Here is the BIOS version info in the first pic

biostar_pc_01

First off even with the brand new battery, doing a hardware clear on the CMOS (repeatedly), and something in firmware about clearing the CMOS it refuses to save certain changes. Every time it comes back up it says "bad checksum" on the boot post:

biostar_pc_02

I'll go back to the BIOS screen, re-enter things, try to reboot, and it does the same thing again. It's saving SOME data - like the date/time. But not everything I enter into the BIOS, some things reset (like I've repeatedly disabled the floppy drive since there's nothing connected to it and it always resets, other things too though I didn't keep a list, and every reboot gives the same "bad checksum")

Second, it's still not seeing the RAM. I have two 4gb each sticks - running either alone shows up as 3gb visible to the BIOS. (I thought there was some way to get around what I thought was a 32bit problem of having a hole there but that's separate) Running both together still only shows 3gb visible - no matter what slots I put it into, single or dual channel. Unless whatever is causing the memory hole between 3-4gb is also blocking it seeing the full 8gb of RAM.

Third it's acting a little funny with seeing the hard drives.

biostar_pc_03

biostar_pc_04

Basically I cannot simultaneously view a USB stick as bootable and SATA drives as bootable no matter what I do. (and disabling the floppy just means nothing) All it wants to show for options are Floppy, CD/DVD, and either recognized USB key or SATA drive. This is making it hard to install windows.


PARTS LIST

OS - nothing yet, Windows 10 Pro is what will eventually be installed
PSU - Cooler Master GX 750
CPU - Intel i3 540 with the basic heatsink fan combo that came with it.
RAM - 1 stick Crucial 4gb DD3 1600 PC3 - 12800
VIDEO - 2 EVGA GeForce GTX 260 (same issues using 1 or 2)
2 generic HDDs
1 generic DVD drive

I posted an update on my issue as well as my parts list and OS... see the longer post.

All the parts were still sealed in their bags, no oddities, however the battery did end up being the initial culprit... see the longer update post.

Yea... I was afraid it might be that, never really flashed a bios before, was always concerned about accidentally bricking the board.

I did manage to get Windows 10 Pro installed after testing the different SATA devices one by one, and the system runs terrific once it loads.

However, the "bad checksum" still shows up every single time it boots... and Windows will show 4gb total ram but only 3gb usuable "hardware reserved"... but if the the CMOS chip is bad like you say, then that would explain why none of the bios settings stay saved and just reset every time.