I had a problem that sounds exactly the same as the one your having. For me the fix I used it erases every thing, do you have a back up of the files you want if you have any? Here are the steps that worked for me. In my case I think it was caused by a virus that messed up the Master Boot Record. I'm not an expert but this is what worked for me so I thought I should share it.
http://www.tomshardware.com/answers/id-1705446/black-screen-white-underscore-emachines-logo.html is where I got help for this problem from @SchizTech
1. Go to http://www.seagate.com/support/downloads/seatools/
2. Download the one called SeaTools for DOS and burn the .iso image to a blank CD and boot from it.
3. Once your there click on the Advanced Features tab, then click on one that says Erase Drive on the drop down menu. If I remember right there are a few different kinds you want the one that is called something like full erase.
4. Once it's complete (it takes about three hours) try booting from your system restore disks again.