Windows
Every Windows key in this category is a genuine Microsoft license, delivered to your inbox within minutes of checkout — no shipping, no physical box, no waiting. We stock both retail keys, which are transferable between PCs and ideal if you upgrade hardware later, and OEM keys, which activate one device permanently at a lower price. All keys work with Windows 11 and Windows 10 and activate directly from Settings > System > Activation using Microsoft's own servers — the same activation path as a key bought from Microsoft or a physical retailer. MCAKey is a Certified Microsoft Partner and Authorized Microsoft Reseller, so every key sold here is sourced through legitimate Microsoft licensing channels, not gray-market resale. Individual buyers activate a single PC; PC repair shops and IT teams buy in volume to activate multiple systems at once, with the same instant-delivery process either way. If you hit an activation error, our step-by-step activation guides cover the most common Windows error codes.
What's the difference between a retail and an OEM Windows key?
A retail key can be deactivated and reused on a different PC if you upgrade or replace hardware. An OEM key is permanently tied to the first motherboard it activates on and can't be transferred — it's cheaper because of that restriction, and it's the right choice if you don't plan on rebuilding your PC.
How long does delivery take after I order a Windows key?
Keys are delivered by email automatically, typically within minutes of payment confirmation. Each email includes the license key itself plus a link to the matching activation guide for your Windows version.
