I am currently using hp touchsmart 15 laptop which is about 2.5 year old. Recently i would like to upgrade the hdd to 256ssd.

The laptop originally came with oem windows 8 basic. And i upgraded to pro version with valid key purchased after that. When Microsoft offered free Windows 10 upgrade, i upgraded to win10 pro now and using it now.

After reading so many posts i am getting confused with the licensing issue.

I used microsoft media creation tool to downlod the win10 iso file and burn it to dvd already. I am intended to do clean installation on the new ssd instead of cloning.

If i do clean installation with the dvd i created, do i still need to purchase new win10 license or it will activated automatically or i can use back my win8 pro key?

I am quite familiar with old win installation method via bios. With new uefi system, i am not so familiar.  Can i still use bios to boot with the dvd i created and install win10?

Lastly, is it advisable to create multiple partitions on ssd? Would it shorten the lifespan of ssd?

Hope sifus here can help. Thank you very much.