Change the boot order in the bios to CD/DVD then boot fro your XP disk and follow the prompts. Make sure you have all your Motherboard drivers etc before hand you can also download and burn XP SP3 or even slipstream it into your XP disk.
This came O/S installed so I not have a disk.
I can do this from another XP disk but I would like to use the correct
license number for this machine. Can someone tell me how to find this please
before I proceed.
You may have a hidden 'restore to factory fresh' partition which would be far easier and as XP came pre-installed it would have been activated at the factory. This will be preserved if you use the 'restore to factory fresh'.
The key installed on your pc will be the pre-activated key (known as a SLP product key) and cannot be used (it won't work) for a fresh install from a CD/DVD. For that you have to use the key on the sticker on the case and then phone MS to activate.
the COA sticker is missing but I think it did have one when new.
Jelly bean gives me a 25 digit code that it calls "CD Key"
I have done this before a long time back on another PC but cannot remember exactly. As I recall, start from a CD and at some stage there is an option
to select or enter "R". This is not the "Restore Console" which should not be used.
Restore to factory would be ideal if it exists and I can access it.
Do not know the make, motherboard is ASUS P5 VD2-MXSE if that is relevant.
I will clone the drive to another HDD and disconnect it in case anything goes horribly wrong.