Autoload CDs

For whatever reason my new computer has stopped autoloading CDs. I can put the CD into the drive but I have to manually load it up. I have tried accessing the drive, right clicking onto properties, and clicking on the proper action. I have also tried restoring to the defaults. Nothing seems to work. This is, I am sure, a very simple problem but it has been driving me nuts. Looking forward to all your wonderful answers. Thanks in advance.