OEM Vs Retail Copy of Windows

Recently i wanted to move my OEM copy of Windows 7 professional to another system as my laptop crashed,but the following were the startling relevelations.

OEM versions of Windows 7 are identical to Full License Retail versions except for the following:

– OEM versions do not offer any free Microsoft direct support from Microsoft support personnel

– OEM licenses are tied to the very first computer you install and activate it on

– OEM versions allow all hardware upgrades except for an upgrade to a different model motherboard

– OEM versions cannot be used to directly upgrade from an older Windows operating system

Some links to read more on the licensing issues.