Welcome to the forums! I hope you enjoy building computers as much as I do.
First thing you need to do is learn about computers: the components, the companies, basic technology lingo and compatibility (e.g., AMD CPUs don't work with Intel motherboards). If you are unfamiliar with these, check out this guide by lifehacker.com
. It's pretty comprehensive (but not too detailed) and will walk you through the whole process.
Second, identify what you want to do with the computer (playing Space Engineers is one) and how much you want to spend (which you've done). Be sure you make reasonable expectations on both.
Third, before you start buying parts and slapping them together, reach out to the forums and ask if everything looks good. Sometimes we'll see some issues, or we may recommend better (sometimes cheaper) components.
Here is an example of a build that would fit your bill:CPU: AMD A8-6600K 3.9GHz Quad-Core Processor
($104.99 @ Newegg) Motherboard: ASRock FM2A75M Pro4+ Micro ATX FM2+ Motherboard
($59.49 @ Newegg) Memory: Crucial 4GB (2 x 2GB) DDR3-1600 Memory
($44.99 @ Amazon) Storage: Seagate SV35.5 1TB 3.5" 7200RPM Internal Hard Drive
($64.99 @ NCIX US) Video Card: MSI GeForce GTX 750 Ti 2GB Video Card
($149.99 @ Amazon) Case: NZXT Source 210 (Black) ATX Mid Tower Case
($32.99 @ Micro Center) Power Supply: Corsair Builder 430W 80+ Bronze Certified ATX Power Supply
($34.99 @ Micro Center) Optical Drive: Asus DRW-24F1ST DVD/CD Writer
($19.99 @ Newegg) Operating System: Microsoft Windows 8.1 (OEM) (64-bit)
($89.98 @ OutletPC) Total:
$594.40(Prices include shipping, taxes, and discounts when available.)(Generated by PCPartPicker 2014-05-20 18:41 EDT-0400)
Keep in mind, it's only the "tower" - there's no keyboard, mouse, monitor, or any other peripheral you might need.
Hope this helps.