Before I start, I'd like to mention a few things.
I'm quite a newbie, and do not know much about Ubuntu. All I wanted was to be able to have a dual boot Windows7/Ubuntu, the latter being a backup when my Windows get a bit slow. It's been working fine, and I have mostly been browsing on firefox with it.
I have very little knowledge of Ubuntu (I don't know how to do commands, "sudo" things etc). I've looked up my question a few times, and words such as "kernel" pop up, which confuse me.

So please, be tolerant and patient with me! :)

A few days ago, my laptop fell from the desk (cables hanging, pulled on by a foot...). I've had this laptop for over 3 years and it fell a few times (I'm very clumsy), nothing major happened to it appart from a few scuffs. Yet, since this happened, my computer seems to refuse to boot properly, and at the "Grub" ,where you select between Ubuntu and Windows, I get the error "Attempt to read or write outside of disk 'hd0'".

If I try to boot Windows, nothing happens.

I suspect it is due to the computer falling and possibly damaging the Hard Drive, but I am not sure.
I did try and install a few programs before (such as VLC etc) while on Ubuntu, attempting at the "sudo" thingies... Could I have done something wrong to mess up the whole hard drive?

In any case, since this happened, I have not been able to boot my computer, and right now am using an old laptop to post this message.
I have a little bit of knowledge on dismantling laptops, so I removed the hard drive from the laptop and connected it to this one. It does the same error, so I confirmed (to myself) that it wasn't hardware problems of the laptop but just the Hard Drive.

Thank you for your time, and many thanks if you can help me!