Honestly it's just an old PC. 1GB of RAM with a GPU that I have never even heard of. You are honestly better off just getting a 4GB stick of RAM from somewhere so you can get by until you buy a new PC. No software is going to help you on the hardware side of things. I have never liked Firefox since it always seems to have lag spikes as well as moments where it completely freezes for me too, despite having a rig that is more than capable of using a measly browser (specs in sig).