Check the Memory Module!
Open the laptop and if you'
ve 2 modules installed, take out both of them and use a soft pencil rubber for to clean the connector feets. After done trhat, place one Module back in and start the Laptop to see it works, if not change nthe Module Port and try again. Do the same with the 2. Module.
Use an PC and create a bootyable USB Stick with Windows 7 on it. For to do that, download the Windows 7 USB DVD Download Tool from Microsoft: Windows 7 USB DVD Download Tool which could be used for Windows 7 and even Windows 8 for to create an USB Windows 7/8 device.
Check the setup from the USB is ok and work. It's possible that your DVD Drive or the DVDF has some problems.
I would suggest to do a clean and full new installation.