Just as Windows xp/vista,there are 3 types Windows 7 product key:
OEM(SLP, NONSLP, COA)
VLK (MAK, GVLK, CSVLK)
- What can be purchased in shops or online
Suported by Microsoft. Needs activation by phone or online.
OEM: Original Equipment Manufacturer
- OEM:SLP – (System Locked Pre-installation) These keys are preinstalled by the OEM. Data embedded in the BIOS (SLIC), is used to validate the key. SLP keys will work with any OEM SLP system, regardless of the OEM system’s brand. This are the only keys that are able to bypass activation that is, perform offline activation without contacting Microsoft.OEM:NONSLP - (Non System Locked Pre-installation) Similar to Retail, but distributed and supported by an OEM. Needs activation by phone or online.
OEM:COA - (Certificate of Authentication) The OEM:COA (for Vista that comes with a OEM:SLP key pre-installed by OEM) key would be required if a reinstallation is needed, the COA should be affixed to the body of the computer. Needs activation by phone or online.
Volume License Key (VLK) is a term used by some computer software companies to denote the product key used when installing software licensed under volume licensing, which allows a single product key to be used for multiple installations.For this kind of key,activation will be done via KLM server.
- VLK:MAK - Multiple Activation Key
VLK:GVLK - Group Volume License Key
VLK:CSVLK - Microsoft Customer Support Volume License Key
Ok,if you want to know what kind of key you own,you can use the Microsoft Pid Check to check.