If the CPU and board were tested before being sold, it seems highly unlikely the jumpers would need to be changed again. What board, VGA are you using? Photos would help.

Pics?

What PSU are you using? Is it known to be good?

What video card are you using?

What RAM?

Welcome to the forum! 😃
As others already said: The more details we have the higher our chances to troubleshoot.😉

Welcome!

edrahn wrote on 2021-10-25, 19:46:

I recently purchased a Pentium MMX 223 and motherboard. And it doesn't post BIOS. It was sold as working so I'm a little confused.

It would be helpful if you could provide makes and models of your MB, RAM, graphics card (some Socket 7 MB have video chip integrated but most still need an independent graphics card), PSU, etc. Better yet if you have sharp photos.

A possible reason could be the RTC battery; some MB designs would refuse to boot without a working battery even if everything else is perfectly fine. Just a few days ago I fixed a friend's Acer Aspire X1800 (Intel Pentium E5400 on MCP73T-AD) that wouldn't boot simply by replacing its depleted CR2032.

edrahn wrote on 2021-10-25, 19:46:

Do the jumpers need to be set to boot? Should I at least get something even if is wrong.

If the seller had actually tested the MB before shipping then don't bother adjusting jumpers at this moment. Leave it as is (to preserve the state as seller claimed) while look up its official manual (if possible) for default settings to make sure the seller didn't make unnecessary tweaks e.g. overclocking too high.

Thanks for the help.

It's missing a battery, hopefully that's it.