Need to repair operating system on computer and original back-up/installation CDs that came with computer were lost in moving. This is a friend's computer and I am not the first person to work on it! Need those CDs as repair calls for them. Computer barely useable but better than before I started working on it.

Contact the computer manufacturer to order replacement Recovery CD for the particular PC. i_Xp/VistaUser

Gateway system recovery info: http://support.gateway.com/s/SOFTWA...

So long as you use your friends original xp/vista key (normally printed on a sticker on the side of the case) then you can use any xp/vista CD to do the reinstall.