Get your taxes done using TurboTax

I am more comfortable with using CD's to download software. Also I am concerned on what to do if my hard drive goes down unexpectedly and I lose the program that was downloaded. If I have the CD doesn't that allow me to get the Turbotax for a particular year? Will Turbotax keep the past years programs and allow me access to download it again at a later date. May be for Audit purposes.