My God daughter was running a Gateway NV5 when she droped it on the floor. I wont come on now, just says trying to repair the flashes some screen images for a spit second and then grey screen. How can I check the HD?
I strongly believe that a forum will not be able to diagnose nor help you repair the issue.
When a laptop gets a blow, all kinds of things can get damaged or displaced especially on the motherboard. It could be one or a few parts or circuits. Then again the screen lights or its inverter may also have been damaged.
I truly believe that a qualified technician could help you in the matter that concerns you.
You can remove the hard drive and use a USB drive adapter to try reading it on another computer. If it's a SATA drive you can often connect it directly to an internal SATA port and power cable on a desktop computer.
What is the brand name of the drive? Some manufacturers have diagnostic software that is specific to their brand name drives.
Given the messages I would say there is a 90% chance the drive is damaged.