OEM is original equipment manufacturer. People who build the computers from component parts.
The OPK lets them install windows onto a new built PC, add company logos to system info, support information and links as well as additional software, then 'reseal' the computer.
This means the buyer doesn't need to go through a full installation of the operating system (approx 40 min) and is instead greeted with a first run of windows screen; and a quick configuration (approx 3-5 mins).
if you've installed an oem copy of windows you can add your own logo and oem info easier than using an OPK by creating oeminfo.ini file (with the info you want in it) and an oemlogo.bmp (picture you want) in the system32 folder of windows. see link:
What is Vista OPK
Linear Mode
