I have an OEM version of XP PRO that returns a invalid version.. makes you go ummmmmmmmmmmm
I try to update IE and it says I need to install SP1 first. I try to install SP1 and it says the version I am using is later than SP1.
I've had similar problems with both Win98 (when I ran it) and XP when trying to update from MS website.
Two things. The validation of OEM software is different, and there are a lot of people selling quasi-illegal copies of XP, basically CD keys that were licenced for big manufacturers, but being sold to consumers.
I have xp pro and changed computers. I contacted them by phone and got someone in india to authorise my copy. Funny thing is that the phone number given for my area (Seattle) had been disconnected. I used a number for Canadian users no problem.
I am running it on a 400mhz pentium II. When I dump that computer (soon), I'll have to make yet another call. They must hate people that keep moving their operating system from one computer to another.
Microsoft blocks some license keys, especially bulk licensing or OEM keys, that are known to be compromised from updates. If you have a valid key and don't wish to re-install, LabMice.net has some instructions for changing the license key for a Windows installation. Or else, you can call to get a valid key.