unable to install games.Asking for cdrom

[jackal_79]

I accidently deleted my mahjongg game from ubuntu 10.04.Now when iam trying to install it from software center or synaptic, half way through it's asking for ubuntu cd.Eventhough i insert the original ubuntu 10.04 cd,it's not taking it.it keeps asking for the cd.It is same whenever i try to install any more game from synaptic or software center.iam attaching a screenshot.can anybody help?

[uRock]

Go in your menus to System> Administration> Software Sources and click on the "other software" tab, then click the Add CD-ROM button.

[jackal_79]

did that.still didn't work.even after putting cd rom it kept on asking for cd rom in between and got stuck in the end.now it asks for cdrom whenever i try to install anything.how to remove this?