backup an installed game?

[guesswho24]

Good morning everybody!

I hope don`t make you laugh with my absolutely noob question (-:

My problem is, that i want to make a backup of a game which is installed on my
computer but as hard as i try i can`t find the original dvd...hm...

The question is : is it possible in any way to save all data from this game on a cd? i mean, the problem is that there`re several registrykeys which have to be saved on cd also, in order to place them in the registry when i want to install it again, haven`t they?

i hope that you are able to understand me, `cause my English isn`t very good (-:

Greetings guesswho