I recently received a new computer from Systemax, XP preinstalled of course, with a Microsoft key number label on it and it was an SLP installation. (System Prelocked Activation)
As I always do, the first thing I checked out was the restore disc system to find if it had any defects, and yes, using it lost the Service Pack 1 installation which also meant the loss of USB2. No problem for me, but not very clever for an inexperienced user.
However, I didn't want their XP installation for the XP partition I wanted to keep, so reinstalled it from my own XP CD, attempting to use the Windows key supplied. This was refused as invalid, something which I understand is a common problem with new computers. I used my existing number meanwhile. It seems that suppliers take no care to supply the correct number for an installation.
If you have a computer with a preinstalled XP, it's a s well to find out what your correct key number is, don't rely on that label. Unfortunately, in XP the number is encoded into the registry in a way that makes it unviewable.
To overcome this, go to the following site and access the XP Viewkey program, you'll see the link to view your number in the middle of the items shown. It's a tiny program which you don't even install. Just select Open from the download options and it will instantly display your correct Windows key. If you're very lucky it might match your label, but in many cases it won't.
Alternatively. if you want to keep it for future use, just save to disc and again just click the exe file anytime to see the number, again no installation happens.
Here's the link:-