Making a backup of your game media - one copy only - and using it to reduce the wear and tear on your originals is explicitly legal, has been upheld dozens of times in US courts (and the US is lately one of the first places to strike down fair use and personal ownership), and has yet to be successfully prosecuted. Further, if you are only making a copy for yourself, and you use it strictly so that the original media can be archived, then nobody should ever know.

For games which have DRM, as orcishgamer posted before, you have to copy the DRM over as well.

+1

I guess we all have this rule. However the original poster asked, if it is legal. So basically we are giving legal advice.

Uh, btw. something that is forbidden too in germany (at least commercially). Only lawyers should do that to make sure that you get qualified advice. :)

Aye!

It's not that simple. The provisions in the DMCA that specifically prohibit cracking or copying a legally owned copy of a game are in direct contradiction to fair use doctrine and there have already been exceptions granted that will allow certain types of cracking/copying. For example, under the DMCA it was illegal to "jailbreak" an iPhone.... until last summer. An exception was granted that now makes it completely legal to jailbreak your phone. Similar exceptions have also been granted for situations where cracking a game is required for compatibility purposes, such as trying to run a Windows game on Linux via Wine. Really, the only thing that is still clearly illegal under the DMCA is producing a crack, using one is perfectly fine.

#1 rule for backups is if you can't restore then it's not a backup.

So if you backup a DRM protected CD and can't use it because the DRM doesn't work anymore then you have a useless game.

So as TheJoe said you'll need a crack more often than not for CD games with CD based DRM.