Here's a list of Product Codes. This is the first number of the Product ID. 55274 : XP Pro generic OEM or Volume License (VL is a special case of OEM) 55276 : XP Pro (upgrade) 55276 : XP Home (?) ' 55277 : XP Home generic OEM 55285 : XP Pro ' 55661 : XP Pro (retail) 76475 : XP Home (upgrade) (?) 76477 : XP Home Royalty OEM 76487 : XP Media Center Edition 2005 76487 : XP Pro Royalty OEM 76487 : XP Pro volume license (with '640' channel ID) 76500 : XP MCE 2005 (XP Pro with AD/GPO disabled) 76588 : XP Pro x64 OEM The second number is Channel ID 000 : Other (includes some retail, upgrade and evaluation versions) 007 : Retail 009 : Not for resale - bundle 011 : XP Home Upgrade OEM : OEM (This does not specify royalty or normal OEM) 270 : Volume License 296 : MSDN 308/347 : Microsoft Action Pack subscription 335 : Retail 640 through 648, 652 : Volume License (usually generated via 270 CID in setupp.ini) 699 : Volume Windows XP Tablet Edition 071 : Pos