First of all I do not know a lot about computer operating systems.  I have a 3.5 year old Dell XPS 200.  Last night our computer froze during a Google search, I did a control-alt delete, which told me it was not responding so I ended the task (all of this I am familiar with) but that did not work;  I waited a few minutes more and then finally turned off the computer.  When I turned it back on I got the message "Drive O not found. Serial ATA, SATA-O.  Has my hard drive failed?