George, 1st off, the OS, generally, could care less if the Ram came from XP. The capabilities of the motherboard are far more important.

As we don't know the precise info on the ram you sold this person, OR the precise info as to motherboard make or PC maker's name and model number that the buyer put the Ram into, makes it virtually impossible to give a definitive answer.

Compatiblity could be a major issue at the buyer's end. I've seen mobos that uneducated users have tried VERY hard to insert PC100/133 sticks into a DDR slot and vice versa, then wonder why it doesn't go "snap" or the retaining clips break :confused: Not saying your buyer tried this tho, lol.

If you plan to persue the issue with the buyer, get more details from them with regard to mobo and or PC maker's info and ask them to define "doesn't work". i.e. Did they use just your stick of ram by itself or was it added to an available empty slot? The size of ram (MB). EEC or non-EEC, they have and the MB that you sent them?



Too many variables/possibilites here.

Cheers, Ed