You need to buy a complete new copy of XP in either Retail or OEM flavour Voonee.
Ask if you are unsure of what I mean.
No because you do not have any installation media, in other words a Windows XP operating system disk.
Forget all about the 25 digit/character key underneath the machine ok.
Get either a retail or OEM version of XP.
Both versions will have a new key that you can use.
Technically you can use an oem version of XP to install and then use the key on the bottom of the laptop to install. However, you must call microsoft to have them activate it as it won't activate online. I did this procedure on a clients laptop using my copy of the cd but the code on their machine. Microsoft gave me a new activation code with no issues. Just make sure you use the same flavor of xp that was installed on the laptop, most likely home not professional.
Technically you can use an oem version of XP to install and then use the key on the bottom of the laptop to install.
Technically this is incorrect because an OEM version of any operating system is not transferable whatsoever.
By doing a new install, irrespective of activating it, one would be using an OEM that was previously used to do an install on another machine and this would be against the Microsoft EULA for OEM software..
You aren't transferring anything. OEM is OEM. Doesn't matter if its installed on store bought pc or you used an OEM disk. All that matters is that he use the license code on the bottom of the laptop. If Microsoft had no issue giving me another activation code then there is no worry about it. The reason why the code on the laptop won't work for activation is because all OEM manufacturer license keys have been deactived my Microsoft.
A retail version of XP would give you the opportunity to not only install it on a machine but also a portable device too, in other words a laptop.
what questions do microsoft ask