And don't expect much from a 10 year old PC trying to do the very computationally demanding task of real-time video encoding.
At least you have PCIe v3, so with a decent GPU for encode offload, and careful OS and OBS settings/optimizations, you might be able to do a simple setup, unless you plan to spend a fair amount of time acquiring technical expertise at OS and OBS level. Or getting someone to set it up for you who has that expertise... and that may well cost more than a new PC would.. sorry.
Good Luck, ... I'm just looking to temper your expectations.
There are numerous threads already for OBS settings for under-powered systems. Browsing through those other discussions may help you
