There are loads of software utilities that will extract your CD Key from the registry - but as you have just created a brand new registry without a key installed there is nothing for it to report back.
Assuming the Vaio was legitimately supplied with XP Home, you need a Sony Vaio XP Home restore disk set for the same model (or a Sony OEM installation disk for the same model).
You DON'T need to install using a key, the OEM Restore CD will recognise the system board and rebuild the XP installation over the top of it.
OEM restores do not use the CD Key on the Certificate of Authenticity as the registry is rebuilt onto the drive & not installed. Installation CDs will ask for the Key on the sticker before they run but if you have not used precisely the correct version of installation disk the Key won't work.
Microsoft will sell you a valid key over the 'phone if you need one.
Your alternative route for the Vaio depends on its age. If it was built post 2003 it will have a 5Gb hidden partition on the drive containing the (German) installation which you can restore by holding down the F10 key when you switch the machine on.
As the window will be in German you need to select the middle of the three options. This will restore XP Home (German) fully licenced.
(If you have reformatted the entire drive during the installtion process you may find this option is unavailable)
Pre-2003 Vaios come with System Recovery CDs
From a licencing point of view Microsoft's view is the Vaio came with a licensed version of XP Home provided by the manufacturer. This OEM version cannot be transferred and if you want an English version you should buy a replacement copy of Windows.
Thanks.
The machine does have a second partition, which was reported when I installed XP Pro last night. I left the file system alone, so it's still there.
So I could restore the German XP Pro build, but would then be back to square one.
It sounds like buying a new copy of Windows (is XP still available?) is the only option then, if the product key on the case won't work with 'any' XP Home install. Switching language should be a fairly basic operation in XP ... I had no idea the OEM installs were restricted in this way
