Now, the moment of truth -- it's time to turn your machine on and see if it works. If there's a switch on the back of the power supply, make sure it's on. Also make sure that the power supply is set correctly to 110 or 220 volts (some power supplies do this automatically, others have a switch or a slider).
Then, push the power switch on the front of the case. In the ideal case, four things will happen:
- You'll see/hear the fans spin up.
- You'll hear the hard disk spin up.
- Lights will light on the case.
- You'll see something happening on the monitor to indicate that the motherboard is working.
If you see/hear all of that happening, you're successful. You've created a working machine. Using the manual that came with the motherboard, you can enter the BIOS screens and make sure everything looks OK. Chances are you'll need to set the machine's date and time, but that's probably all you have to do. Everything else is probably automatic. All the drives will be recognized and auto-configured. The default settings on the motherboard will be fine.