From the Steam Store page:
Build your very own PC empire, from simple diagnosis and repairs to bespoke, boutique creations that would be the envy of any enthusiast. With an ever-expanding marketplace full of real-world components you can finally stop dreaming of that ultimate PC and get out there, build it and see how it benchmarks in 3DMark!

PC Building Simulator has already enjoyed viral success with over 650,000+ downloads of its pre-alpha demo and has now been lovingly developed into a fully-fledged simulation to allow you to build the PC of your dreams.