i want to install it in window xp. I can't really understand korean too.
You are in the wrong place because we don't support Windows here. This is a Linux forum. If some kind person knows the answer to your problem, he or she may try to help you out, but don't hold your breath.<g>
My guess is that you need to install a Windows XP driver for the webcam before you try to use it. I did some mild googling and couldn't find a driver for COSY anything and the Korean Web page was no help. But I didn't try that hard, so you may want to do your own Web search.
If you can't find the driver, I suggest buying a new webcam. You don't have to spend much if you don't want to. A needed driver will be included if you get a new webcam.
A good place for help with Windows XP Home and Vista Home and Ultimate is the CompuServe Windows Support Forum. The people are knwledgeable, helpful, and nice. Go to http://community.compuserve.com/winsupport
. In order to post a message for help, you need an AOL or AIM screen name. If you don't have one already, when you get to the Windows Support Forum click on Post a Message under Welcome, Guest. That will take you to a signup screen. There is no charge, no software is installed on your computer, you won't get any spam as a result, and you can keep your e-mail address hidden. You access the forum through any browser.