does the elder scrolls oblivion require the cd to play on the pc version?

To Install it, you will need the cd, but if you've already got it installed, you can use a no-cd patch/crack. You can easily find one by searching on google. Basically when you put a cd into the computer to play a game, the entire game's already installed on the computer. The idea of having to put the disk in every time is to confirm that you've actually got the disk and haven't just downloaded the game off the internet. The no cd crack/patch is a file that starts up when you load up the game and tricks the game into thinking the disk is there, even if it isn't.

I hope this helped! : )