Windows won't boot. Windows installation disk won't boot. (Windows 7)

[Madd]

So the problem started something like a month ago. Computer took really long to boot up, and when it boots up it is really slow and freezes on a single hover over a desktop icon, and the little red light on computer is constantly on. After some 15-30min the red light is off and it's not freezing anymore, but sometimes is really slow when doing some action. Eventually, red light becomes active again and it freezes with no other option than restarting the computer. I thought of reinstalling the system, but I had some work to do so I thought about finishing it as much as I can and then reinstalling the system. But, few days ago it stopped booting at all. Sometimes it's stuck on Windows loading screen, sometimes it shows a black screen telling that a recent hardware or software change is preventing Windows from starting and gives me two options:
1. Launch Startup Repair
2. Start Windows Normally
Both of the options gets me nowhere. Startup repair doesn't fix anything. Last log says this:
Root cause found:
A hard disk could not be found. If hard disk is installed, it is not responding.

I tried booting from my system CD, launched CMD and typing some commands like bootrec or bootsect.
Nothing worked. Eventually, I tried booting from CD again and this time, I couldn't boot from disk. There is no message that says Press any key to boot from CD or DVD...
I forgot to mention that Safe Mode worked a couple of times, but now it won't.
Also, when I managed to boot in installation disk, it showed that installed version is Windows 7...(recovered).
So basically, now I can not run anything.

Some computer info:

Windows 7 Ultimate x64 SP1
AMD Radeon HD (can not remeber the number, probably something like 6450 i think)
4GB RAM

Strangely, it's all I can remember now, I ll update if I remeber more

 

[Megahertz07]

I would say that your disk is dying.
Boot with the win 7 installation disk, go to repair, open a CMD window and type chkdsk c: /f
If it finds bad blocks or bad clusters, replace the disk (buy a 128G SSD for windows and programs and a HDD for data)