Some companies provide you with a separate copy of windows xp like Dell did for my desktop. However, since your’s is Sony, I doubt they would have provided you with one. Secondly, as Erik put it, it’s OEM so it’s meant to be installed on just that TR laptop (or may be another sony machine too? :?), but even if you did have a XP home retail disc, it’s highly unlikely that MS will give you a retail serial # for that OEM one.