Windows licence / serial number question

[Greboth]

Afternoon all

Building a new PC for a family member and trying to do it as cheap as possible so I was going to use their copy of win xp. However since getting their old PC it is a pre-built Dell and only has a recovery cd, now this isn't a problem as I have an XP CD lying around to use. Now I know it legally works on 1 serial = 1 PC, though gets a bit blurred due to upgrades and wipes etc so can re-use the serial numbers (or get new ones if need be) but I have no clue how it works with pre-built PC's, so;

- When buying a shop built CD and comes with windows pre-installed do you actually buy a Windows licence? I presume Dell have a bulk licence which they use on all their machines and so isn't really the same as buying a personal licence and so isn't re-usable (for lack of a better word)

- Depending on the answer above, no serial number is in the documents so if you can re-use the licence any recomendations on how to find the serial number from the existing install?

Thanks for advice, Greboth.

 

[Greboth]

Motherboard needs changing as PC is 8 years old. Confirmed what I thought though, thanks for replying.

 

[Greboth]

what you should do is purchase a new windows 7/8

what you should not do is install XP and use the serialnumber from the side of the case...

you have to be careful because should you accidently get a WXP oem disk and install it using hte serial number from the case it will work fine and you will never know that you did something wrong...

(on an oem install of xp the serial number extracted by MJB is usless)

Oh I see, well thank you anyway. It would have been so easy for such a pc noob to just use that code anyway and do something wrong....

On a slightly un-related note, I was reading the other day though I don't know how true it is that Microsoft didn't have checks in place on XP as they have on later ones so it is possible to re-use the codes again and again.