Unable to recover Windows using Startup Repair

Hi everybody!
First of all, forgive me for my bad english, it's not my mother language, and I apologize if I didn't post in the right section.
Anyway, since this morning I am unable to start Windows 7, and everytime I open my pc I'm greeted by a menu that asks me to choose a recovery tool. I tried all of them without success, because even the Startup Repair is stuck on "Checking errors". So I searched on the internet and found a guide from this forum:
Startup Repair Infinite Loop Recovery

As written in the guide, I go to the Command Prompt, but whenever I follow the first step and write "C:", either the message "The parameter is incorrect" or "The request could not be performed because of an I/O device error" appear.
I checked and the command "D:" works fine, but my Windows isn't installed there.

Is there a way to fix this problem? I need the computer as soon as possible and with me I don't have the original Windows disk. Is it possible that the hard drive is broken? I really hope not though, because I really need it these days

The computer is an Asus laptop?
How many disks you have?

It can be that you have a disk failure.

Boot from the win7 installation disk, go to repair and launch command prompt. Type:
dir c: If it gives you a list with windows on, type
chkdsk c: /f

or
dir d: If it gives you a list with windows on, type
chkdsk d: /f

If it gives you bad sectors or bad blocks, boot from a Linux USB flash drive and try to save your data on another disk.