New build, same HDDs: Need to reinstall Windows?

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1

Hello to you fellow Tekkers!

Being on an non-OC'd i7-920 that's starting to ache, I'm planning on moving onto a mini-ITX Haswell system — a 4670k inside a BitFenix Prodigy (possibly the Prodigy M refresh when it comes along) — but I want to keep my two Seagate Barraccuda 1 TB HDDs. The C: drive is only 20% or so full, but it has a volley of programs with registration keys (Vegas, Photoshop) and important magic stuffing on it.

The problem is, my current Windows installation is OEM: it's a Dell computer I bought back in 2010 (hence why I can't overclock the 920).

How should I exactly go about this? Will I have to reinstall Windows? Get a new license?

Thank you for taking your time to read this and helping me.

2

I've been asked to re-activate my windows previously when I put my HDD into a friend's system, so I suspect the same might happen to you too. Not sure if you'll be able to carry the license over.

3

Welp, guess I'll have to phone up MS tech support or spread my cheeks and buy my own license.
Buying a prebuilt PC and not even owning the Windows license. One of the great errors of my life, that. 

4

I did this before, transfered a 500GB from a pre-built PC to my new custom built one. Everything will work fine, just remember to remove the drivers and install new ones for ur new PC.