I need some advice on my pc

So I have recently taking an interest in pc gaming after finding out my shit pc can run fallout new Vegas. But after 3 days of play the game won’t work on my pc anymore for some reason. But now I want a pc that can run older games around 2013 and down on pc. Mainly because I’m a console player and I only have interest in playing older games that I’ve played before but this time modded. Any advice on a cheaper prebuilt. Or a good budget build I can put together.