Latest version of OBS is 30.2.2
Undo changes you made on the advanced output.
Run the Auto-configuration Wizard (tools menu) selecting recording as main purpose. Be realistic, your computer is old. It could be that you can't record over 720p 30fps.
Apply the settings the Wizard gives and RESTART OBS.
Now test it as is.
Notice you're in simple output mode. Keep it like this. You don't need nor want advanced output.
If the test went well, now you can change the quality preset for a better one and test. If it goes well, test changing other settings like the fps or the resolution.