I'm having some difficulty with a GT 1030 card (02G-P4-6338-KR) on an older computer. An eMachines W3653 computer, ECS 945GCT-M3 motherboard. It doesn't start normally, and the system will only start at all if the CMOS battery is removed and I don't even try setting anything in the BIOS settings. I've been told elsewhere that it's because of the lack of UEFI on the system.

I am considering purchasing a GTX 750 Ti SC (02G-P4-3759-KB) to use with it instead. Does that card support legacy BIOS?

Then I have to say I'm perplexed, and don't know what the problem is.
 
With the GT 1030, there's just a blank black screen unless the system's BIOS has been freshly reset by the reset jumper, or just turned on after plugging back in with the CMOS battery removed. Even then it seems to briefly turn off (the power led and fans stop for a moment), and come back on a couple seconds later before it shows the POST screen (which complains about the wrong settings) and then continues with boot.
 
Thanks for that product suggestion, though.