I have a computer a friend gave me. The hard drive was toast. I replaced it and the PC is running great. It has a windows COA sticker on it. The original restore disk are long gone. Does a way exist to legally reinstall windows on this pc using it's COA? I left out, it's windows XP. I have two retail versions of XP Home edition. Both are currently installed on PCs. I didn't know if I could use those to install, but somehow use the COA from the other PC. I don't remember what XP version the "new" COA is for. It's on the stricker but I am not near that PC.