What MS says and what they do are two different things. According tot he EULA, with the OEM version:
1. You get squat from MS Tech Support
2. You can not use the OEM OS to upgrade to Vista
3. You can not ever use that OS on another box
Let me tell you my experiences related to Item 3 and OEM.
A. Built my 11 years old's (Son No. 3) box....well actually he did all but mount the CPU and Cooler.....of course I was holding his hand the whole way. We got done and did the OS install and activation via phone as he had no internet in his room since I hadn't run a cable yet. Then I updated all the drivers to latest version and we lost sound. After a dozen tries at various things, I gave up and wiped the HD and stared again, this time sticking with the "old" sound driver.
When we went to re-activate, again by phone, MS refused. Accused me of multiple build sand trying toi get away with something. After 3 days of yelling and e-mails they let me reactivate.
B. Son No. 2 upgraded his RAM and gave two sticks of his old 512's to his brother. This was like 2 months ago. So Son No. 1 pops in 1 of the sticks (MoBo only had 3 slots) and turns on box. Windows boots and notes a change in hardware configuration....and wants to reactivate. Now MS says you need to change like 7 things before you are supposed to have to do this but I figure no bigga deal and tell it to do itself over the net. It says it can't find a internet connection. So I reboot and same thing. So I boot Firefox and FF has no trouble finding a internet connection. So I try authenticating manually and it still won't go.
I call MS, they tell em since it is OEM, I have to pay for tech support. I tell em to scratch my ass.....this is not a technical problem it's customer service problem. They give me two more product ID numbers and it still won't work. I go up to 2nd level support and then a supervisor who both tell me I am trying to pull something. I say screw em and figure he will go back to the 1 GB.
Take out the stick and reboot and now back the way it was originally, it still won't go....wants to authenticate via internet on boot but can't find internet even tho everything is the same. So I reboot and tell it no, then after verifying again that FF works fine, I try manually authenticating and it works (again, with just the original two sticks). So now I figure, it wouldn't dare try and make me authenticate twice within 5 minutes so I pop the 3rd stick in and reboot and now it doesn't notice and is no problem.
BTW, ya might wanna do this. Buy a copy of Vista Business /Ultimate and then tell them you want a downgrade to XP. Put XP on son's box....and put Vista in a drawer till ya need it.
http://asia.cnet.com/crave/2007/09/24/downgrade-your-vista-to-xp/