Using old HDD in a new PC build

[laughingman25]

Hello. First time using this site for my own purposes. I was just wondering if it's possible to use the same HDD I had in my old computer I built, except on a new computer that I am building. All the parts are new, so a new motherboard and everything...

The thing I'm concerned about is the operating system. I'm running Windows 8.1 64bit that I installed using an OEM. I figured I'd do the same with a new OEM I got on this new computer (same exact OS), but I'm not exactly sure how that would work considering it's got the windows files already on it? I haven't opened the disc yet because I want clarification on this first before I void anything and any precautions or steps I should take so I don't corrupt anything.

I hope I have clarified enough.

 

[mbreslin1954]

Physically install the old HDD from the old computer into the case of the new computer and connect it up (data and power). Boot from the new Windows installation disk. It will boot up and show you the hard drives it can detect (there should only be one). Select that, it will show you the partitions on it. Delete all the partitions on it so it is all unpartitioned space, then click Next and let Windows divide up the disk how it wants (it will create at least one very small, hidden partition and then a very large C partition).

So tell Windows installation to delete all existing partitions then tell it to install. Very straightforward.