DiskWarrior DVD revision 1107 was released to start up the new MacBook Pros (introduced February 24, 2011) and the new iMacs (introduced May 3, 2011). Some newer iMacs with wireless keyboards have timing issues when starting up from any DVD. Instead of pressing the "C" key immediately upon start up, wait for the startup chime and then press the "Option" key. This will bring up the Startup Manager which will allow you to choose the DVD as a startup disk. If your wireless mouse is not working in the Startup Manager, use the arrow keys to choose the DVD, then press the "Return" key to continue starting up.