LOST INSTALLATION CD
You can download the drivers you need from Samsung. There are a few different versions of the YP-K5, so I'm not sure which one you need without the device in front of me, but it should have a full model number on it (YP-K5AB, YP-K5QB, etc).
Go to this site:
and enter the model number. It will take you directly to a list of downloads. You need the drivers, but you can download the manual as well, should you need it.