BleepingComputer.com: Help-"Remove disk or other media" Error

Hello, well I was reformatting my computer and an error come up I can't recall what it was now but it was unable to install a file. It said hit enter to retry so I tried but it wouldn't do nothing. So I had to exit the install I took the disc out and found a small crack in the disc. Well anyway now when I start it it gives me the "Remove disk or other media hit any key to resart". I tried changing the boot sequence but that didn't do anything. I really don't know a lot about computers so I need some help. Thanks in advance.