The first thing to consider is getting your money back. If this was supposed to be in working order, it's possible it got shaken up on its way to you or it didn't workk when it left the seller.
The hard disk has lost association with the rest of the working parts. Use the computer you're posting on to download a Linux Operating System - I suggest PCLinuxOS from http://www.pclinux.com - and use ImgBurn to burn it to a CD.
Use that CD to boot your Acer and then see if it can find the hard drive. Post back if you need to know more than that. If your built-in Operating System - probably a version of Windows - cannot be salvaged, you can install PCLinuxOS from that disk and it won't have cost you anything.