Hello, I would like a good gaming desktop to play some modern games on high quality.It will have to be around the 500$ area and I do not want to build it. Thank you!
For $500 you want to be able to find pretty much anything to play modern games at high settings if you aren't willing to build it yourself. Even then, thats asking a lot.
Your best bet is to turn to eBay and Craigslist and see if you can get a decent used gaming rig cheap.
However, seriously consider trying to build. I built my first when I was 14. It's really easy to do with a bit of research and there are a ton of guides on how to do this. A ton.
Here's an easy guide real quick with my own substitions are the same prices.