So legally you cannot re-image computers with an OEM license. To do this the lowest requirement you must meet is this:
- One Volume License for the Desktop Windows Product that matches what you have. So if you purchased computers with Windows 7 Professional, than you will need a Volume License for Windows 7 Professional.
- Volume License Media for that product
When you purchase a Volume license of a Windows Desktop Os you are actually purchasing a upgrade license. This is different than all of their other products, where usually you are buying a full license. So since they are an upgrade licenses you must have an existing Windows OS on the computer or for the computer (Full Retail Product) to apply this VL to. So you can't buy a computer without an OS and think you can buy a Volume License.
I mention this blog posting because this was news to me. Apparently in the EUA it states you can't re-image using just the OEM Media and I know we all read the EUA :) and know this, errr not. Anyways I hope this helps you feel legal.
You can grab the file Microsoft refers to re-imaging here: Microsoft Reimaging download . As you look at this I recommend giving their license people a call.