http
/www.cnet.com/news/windows-8-moves-to-bios-based-product-keys/
So the first comment is correct.
Basically burn a disc as per instructions and install using the key in your BIOS.
Other:
1) There's no requirement for the SAME make and model. Get whatever is cheapest and reasonable quality. I suggest using PCPARTPICKER to help.
*Some laptops use 7mm drives (height) and won't work with 9.5mm drives. You can use a 7mm drive if the bay supports 9.5mm but make sure you have the 2mm spacer but I would recommend just buying a 9.5mm drive in that case.
2) BACKUP your C-drive at some point to a USB hard drive if possible. I like Acronis True Image. If you'd done that you could have used the most recent copy and simply RESTORED it to the new drive.
3) Recommended drives (USA links):
750GB HDD:
http/pcpartpicker.com/part/western-digital-internal-hard-drive-wd7500bpvx
1TB HDD:
http/pcpartpicker.com/part/western-digital-internal-hard-drive-wd10jpvx
1TB SSHD (hybrid):
http/pcpartpicker.com/part/seagate-internal-hard-drive-st1000lm014
The HYBRID drive will help a bit with bootup time and make Windows slightly snappier. It's also a bit more expensive. It contains only a small amount of SSD so it automatically copies bootup and frequently used files/programs to the SSD portion to make things snappier where it makes the most sense.
Note that the Hybrid benefits on a LEARNING curve so you need several bootups or start/close of applications for it to learn which files to move over to the SSD flash memory.