Hard drive completly useless, what do i need to install new one?

Ok so here's what happened, My hard drive has been making strange noises just like an old one had before, when i went into repair it the guys at this computer tech shop had to replace the hard drive.

So now i know from that experience that my hard drive is completely useless and that i need a new one. since i cant clone the hard drive what would you do in my situation?
what is there to possibly do?

Do i buy a new hard drive, and also buy a new windows program? Or does the hard drive come with a windows program already on it? or is there no need to buy a new windows 7 or vista program?

Remember i have a PC tower that has NO hard drive. what do i do to get my computer back and running? Thanks guys.

You need to purchase a new hard and you need to purchase windows unless you have a keycode. Then you can just download the iso of your licensed version from here.

Official Windows 7 SP1 ISO from Digital River « My Digital Life

Burn the iso to dvd using Imgburn at 4x speed.

The Official ImgBurn Website

IF you were having a licensed version of windows than its not the problem just ask a friend to download it for you ......... better make usb bootable and install it from there ( It would save DVD money plus require less time :) )

AND remember to use all four screws on your new hdd ..................