HDD failure?

Not Sure Where To Put This, I'm New. Hopefully this is the right place.
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I bought a Toshiba Satellite Windows Vista laptop about 3 years ago and recently a friend of mine installed Windows 7 on it and it didnt remove the original Operating System, Windows Vista.

So it was working fine for about 3 days untill one morning it started displaying this after the Toshiba Logo at start up:

Immediately backup your data and replace your hard drive. A failure may be imminent: Press F1 to continue.

Now when I press F1 it just constantly repeats messages that make no sense to me, but if you press Esc while it repeats those messages it cancels the whatever its suppose to do and brings me to a menu that asks me what OS I want to launch (Vista or Windows 7) both of them just keep loading forever and ever...

A friend told me that I need to wipe out my HDD and put any OS on it, he told me I need a Boot CD for that.

Basicly, all I need to know is where to get a Windows Vista/Windows 7 Boot CD or another way of fixing this problem.

Note: I can not access my desktop or anything, its like both OS' are corrupted.

P.S. I've tryed a couple different things found on Google like holding down some buttons and stuff to restore to factory thingy but that didnt work.

I'd prefer awnsers as to where to get a Boot CD, but I'd appreciate any other suggestions.

Drive is dead, a boot CD won't do you any good unless you also replace the hard-drive.

Take out the drive, buy a new one. Use your operating disks to install Windows again. If you don't have any, you can buy a copy in lots of places. I'd avoid ebay though, too many fake or illegal keys on there.

Get an external enclosure for your existing drive, see if you can get any files out of it.

If you don't have the original Vista disks that came with the laptop, you can contact Toshiba and order a set, will be much cheaper than a new copy.