Sounds like a bad hard drive, or the hard drive may not be connected correctly. If you have recovery disks, you can replace the hard drive and reload the system. If you do not feel comfortable with this, I would suggest you contact technical support in your region, to inquire about repair.
Please join me in congratulating IronFly who is the first Acer Community Member to achieve the rank of ACE Pathfinder. IronFly has shown a consistent willingness to help others and has worked hard to earn this new Rank. Congrats and Thank You IronFly.