Question: If I get a new hard drive, will it delete windows 10 from my laptop?
Yes.
You could always create a back up but as the drive is faulty you might be better off starting afresh with a clean install.
This laptop was originally a windows 8 but I updated when they gave out the free windows 10 update.
When you did the upgrade you were given what's called a digital licence which is stored online.
The licence is tied to the machine you upgraded from.
You can visit the download page here:
Link Removed and use the Media Creation tool to download a copy of Windows 10 so you can either burn it to disk or USB.
When you install windows 10 and come to the activation page all you need to click is 'I don't have one'...