回复：再请教：两年前买的正版WindowsXP，现在重新安装一下电脑，结果不知为什么，原光盘还在，但不知把安装码弄哪里去了，请问

Yes, you do if you purchase the OS separate from your PC. If the OS comes with your PC, like DELL, HP etc, there should be a product key on your PC and you don't even have to use this key if you reload the OS with the OS CD provided by them.