Windows XPSP3 CD will not detect previous installations?

[snagrat]

I am trying to do a repair installtion on a PC running XPSP2 with a XPSP3 CD.

I downloaded XP with SP3 from the MS volume licensing site so I know it is legit and not a duff copy. I then used nLite to install the relevant SATA drivers to the installation.

Now everytime I try to repair an installation with the CD it does not detect any previous versions of XP like it always has done before.

Is this a new SP3 thing? I tried building from scrath and then repairing to see if it would work then but it still doesn't find previous installations.

If I use a XPSP2 CD then the installation is found and the CD will repair it.

Any ideas?

 

[Duke]

I've had that before when there is a mismatch of service packs or variations of installation media (i.e. OEM vs the manufacturers OEM disk which is sometimes not the same).