Mel - not to alarm you, but when something similar happened to my Dell, it crashed not too long after that.

BACK UP your pc asap.

My laptop was getting a boot error, asking for a cd to boot. The boot sequence switched itself and the only way I could boot it up was to go in and reset it back to *boot from hard drive*. Worked for a while, but still got an error msg - I forget just what that said.

Got blue screens, all kinds of stuff. DS did save all my stuff. I got a new hard drive and put it in, ds put my files on it for me, no probs since.