I am wondering how computer shops deal with installing Windows multiple times. I understand shops can buy OEM packs for installing and setting up new machines but the scenario I am most curious about is when a customer brings in their machine to be fixed. Many times they do not have a Windows disk. They only have their product Key. I would imagine a computer shop must have to assemble a collection of every version of XP, Vista and 7 so that they can re-install customer machines that only have a Key. If this is the case, how do the shops get this generic set of all the Windows versions?
Also, what about the difference between customers who have an OEM version installed or retail? Would the shop need separate disks for that?