Clean Install of OEM OS

I have 2 questions that relate to a "store bought" PC with OEM OS.
Instructions for doing a clean install using the COA key are often given. Legal of course and abides by the EULA.

1) Why do you need to "find" an install disk. Why can't you download this for activation with your legal key?

2) An OEM OS has a different authentication process to a retail version. As I understand it the OEM authentication is based on motherboard identification and little further to do with MS. Whereas, the retail version authentication is always under the watch of MS.
How is authentication handled when you do an OEM OS clean install?

whs said:

ad1) I would think that one could download a .iso from a site like this. But then you will have to burn the .iso to a dvd too (unless you use it in a virtual machine). I do not know how safe that site is because I have never used it myself.

ad2) I have installed a few OEM versions from purchased OEM DVDs (I got them from NewEgg). There was no difference in the authentication procedure than with a full retail version.

Thanks whs
but Q.2 still puzzles me.
Like many people who buy a PC now. The PC manufacturer has the license to install the OS on their machines. But even with the bought OEM OS they are locked to the PC. A full retail OS is not locked to your PC.

PS: I understand you recently had an activation issue by restoring an "old" image. I don't think an OEM OS would have the same problem. If it did I don't think MS would sort it out for you.

Thanks all - useful info Greg.
WHS,
thanks again
The activation issue/problem bothers me. Maybe MS in the US are more understanding to their customers. Based on previous experience I don't think they would be as supportive in my part of the world (OEM OS=hangup).

OEM activation that happens in the factory is different from how it happens when you do a clean install.

In the factory, the activation process is offline, which means MS servers are not required to be contacted. This is because MS permits large royalty vendors like Dell, HP etc. to deploy a single win7 image across multiple computers, then activate them with a particular brew (Bios marker plus digital certificate plus standard key), to save them the hassle of entering the key and activating 1000s of computers one by one online.

So if, E.g., you run a mgadiag or slmgr -dlv, you'll see the license type OEM-SLP. SLP stands for sytem locked preinstallation which means the SLP keys used to activate.

OTOH, when you do a clean install, you use the COA key on the sticker. This process is the same as retail activation. You go through the usual loops- online activation, if that doesnt work then call MS. The license type will now be OEM-COA (not OEM-SLP).

Feel free to ask.

Bill2 said:

OEM activation that happens in the factory is different from how it happens when you do a clean install.

In the factory, the activation process is offline, which means MS servers are not required to be contacted. This is because MS permits large royalty vendors like Dell, HP etc. to deploy a single win7 image across multiple computers, then activate them with a particular brew (Bios marker plus digital certificate plus standard key), to save them the hassle of entering the key and activating 1000s of computers one by one online.

So if, E.g., you run a mgadiag or slmgr -dlv, you'll see the license type OEM-SLP. SLP stands for sytem locked preinstallation which means the SLP keys used to activate.

OTOH, when you do a clean install, you use the COA key on the sticker. This process is the same as retail activation. You go through the usual loops- online activation, if that doesnt work then call MS. The license type will now be OEM-COA (not OEM-SLP).

Feel free to ask.

Thanks Bill2.
(1) So can you still move from OEM-SLP to OEM-COA using the COA key that's on the computer.
(2) OEM-SLP are authenticated differently and maybe more robust to accepting older images made from the same computer?

(1) So can you still move from OEM-SLP to OEM-COA using the COA key that's on the computer.
(2) OEM-SLP are authenticated differently and maybe more robust to accepting older images made from the same computer?

1) Yes, you can. The COA key is exactly what it says- proof that you purchased genuine windows and a safety net to reactivate the system should a fresh install be required. There is no bar to moving from one type of activation to another. Practically speaking, once the OEMs stopped giving out restore disks, this is the only way left for end users to reactivate.

2) The only reason OEM-SLP are authenticated differently is the convenience of the royalty OEMs. See, OEM sales are a very large proportion of MS profits and MS and OEMs have a symbiotic relationship. This method permits painless activation, because the image already contains the certficate and key required to pair with the bios flag.

So it seems to me that if
(1) you have a factory recovery capability (made the disks)
(2) Cleaned out undesirable trial software ("bloatware")
(3) Are making good reliable images

there may be advantages in just sticking with the OEM-SLP authenticated system.
I am guessing that when you do an online check that the OS is authentic MS may just look for some form of valid OEM-SLP certificate.