I just got a backup of grand theft auto for my pc that my mate downloaded and burned to cd. when i put it in my cd drive all that is on the disk is 3 files. they are 2 iso files and an info document. can i install and play this?

Hi aye,

Iso files are image files that need to be burned to disc, you can burn an iso with most burning software (I use nero).
Alternatively you can extract the data from the Iso files with Winiso (http://www.winiso.com) or isobuster (http://www.smart-projects.net/isobuster).