New case

[BCaused]

Nvm it was a problem with my drivers

 

[DSF]

It shouldn't be necessary to spend that much on a case just to keep the computer from overheating. It's fine if you want to of course, but let's get some basics out of the way first.

What is your current case? How many fans are you running, and in what configuration? What sort of environment are you running the PC in? General heat/dust levels for example.

Have you tested with hardware monitoring programs to make sure that the PC is actually overheating? Power supply, motherboard, RAM and driver issues can all also cause random restarts.

If you have done that testing, is it the CPU or GPU that tends to overheat first?

Are you using the stock cooler or an aftermarket cooler? Are you sure the the cooler is properly installed?

Sorry to throw so many questions at you, but they're all important to ask before you go out and buy a case.