Hi, Why doesn't MS use seperate keys for Windows server STD and Windows Server ENT ?

I think you mean: Why does MS use separate keys for Windows Server Standard Edition and Windows Server Enterprise Enterprise Edition. Microsoft Windows Server Enterprise Edition provide more functionalities compared to Standard Edition. As an example, Exchange Server can not be installed on Standard Edition because it requires Enterprise Edition. So, due to many differences and the fact that Enterprise Edition is more evolutive than Standard Edition, the prices are not the same and you can not use a Windows Server Standard Edition key to activate a Windows Server Enterprise Edition. This posting is provided "AS IS" with no warranties or guarantees , and confers no rights. Microsoft Student Partner Microsoft Certified Professional Microsoft Certified Systems Administrator: Security Microsoft Certified Systems Engineer: Security Microsoft Certified Technology Specialist: Windows Server 2008 Active Directory, Configuration Microsoft Certified Technology Specialist: Windows Server 2008 Network Infrastructure, Configuration