I had what I suspect was an MBR corruption - or at least a corruption of one of the files loaded during bootup. The system would get 60-70% through booting, then flash a bluescreen and return to the start of the boot process.
The only way I could get my system to boot was bia going to the recovery CD and re-installing the OEM version that came with the machine initially.
Having done that I was in the process of patching up the OS to get it back to where it was. I downloaded and installed SP1 but before I could go any further I got the message that "this version of Vista is not validated" and was informed that I would be cut off from updates, and have access to the control panel etc removed until I validated the OS.
Not particularly bothered with that in itself as I thought it would be a minor thing to re-validate the OS. However when I tried I simply got the message that "this version is no longer available" and the only
options I was then give was to pay 100+ euro to upgrade to Win7 or report my OS as a pirate copy.
I have tried searching for what to do to correct this - as I cannot believe MS can legitimately cripple my machine simply for being 4 years old (some software I have will not run without SP2), however my google-fu hasn't delivered me a clear answer on how to proceed.
Anyone else had this problem? Or know how to approach it?
Please do not just say "upgrade to Win7, it's better anyway" as I will be getting a replacement PC later in the year so I do not want to shell out for a Win7 licence now when I will be getting one with the new machine when I can afford it. I just want my current machine working so that I have something to use for the next few months until replacement kit is bought.
 Once I do get replacement kit though this P.O.S. machine will be wiped and installed with a linux flavour to live out it's days as a file server on the home network.