Chris T Loc: from England across the pond to New England

Perhaps, it's ONLY in America, then, Chris. Yes, it has happened to me. When you buy the OS from a store to install on a Home-Brew - you're buying the license, for ONE PC. You can also buy one for Home Use to install on as many as five machines - for a little more money - but, that's the limit. If you buy the Business version - for a whole lot more - you have a license to install it on as many as 10 PCs. But, that's as far as it goes. When you search for updates - the first thing it does - is scan for the license number. Home Brews - are given special license numbers, to indicate they ARE Home Brews. Then, when the scanner sees it IS a Home-Brew - the upload process fails to initiate. OEM PCs have a different license number configuration - issued to a thousand? PCs at a time. When the scanner sees those license numbers - the Win Update process initiates. If it doesn't see those numbers - it won't!!!!

chrissybabe Loc: New Zealand

You have some things wrong here I think.
An OEM licence works only on a single PC. There is a bulk licence, which I avoided using because although the initial purchase worked out cheaper, over 3 years it was dearer so I stuck with single licenses. These bulk licences (I forget MSs term for these) are the ones that pirates get. And they work until MS catches up with them. If a bulk licence was issued in Thailand, for example, but copies show up in Brazil they know it is pirated and activation will fail.
I have never found anything about what you call home-brew PCs here in NZ.
And there is definitely nothing like a business version of the licence which will allow it to be installed on up to 10 PCs. Not sure either about the Home version allowing installation on up to 5 PCs. I vaguely recall seeing something that might indicate there was a version allowing up to 3 home PCs.
I do know that as long as you don't use the licence on more than 3 installations (not simultaneously but 3 different reloads you can activate it but only if the licencing system only ever sees no more than 1 operating). This allows you to change hardware or reload several times on the same PC (because of hardware issues etc). After that you have to do a manual activation. That's how it was.
Being in NZ I cannot help you with this but I seriously suggest you ask at a local PC shop in the US because there is something wrong here.
This whole industry is built around being able to build your own PC (and that is what all the PC shops are in business for) so I can't believe that millions of home PC builders are able to buy parts but not an OS that can be updated.

Chris T Loc: from England across the pond to New England

Chris - this is the way I've been given to understand it. Home-Brews - a term MS, itself, uses - to define a PC one puts together, oneself - using store-bought components - case, motherboard, CPU, RAM, HD, Video Card, DVD Burner, Power Supply, etc., etc. - and then loading an OS picked up, locally, or from places like Staples and Amazon - are prevented from UPDATING that PC over the Net - here, in the USA.

chrissybabe Loc: New Zealand

Who gave you to understand that ?
Somewhere, somehow you are completely wrong !
You say it happened to you but I suspect you had bought an illegal copy.
Send me a copy of what you have read from MS.

Chris T Loc: from England across the pond to New England

MS indicates that in a dialogue, when you attempt to upgrade a Home Brew!!!!

They also sent out a message, several years ago - INDICATING they'd no longer update Home Brews.

This goes back to the days of XP!!!!