Why is my MacBook Air version 1.1 suddenly going super slow from start up?

Ip think my MacBook Air is dying. It is so slow from start up (try almost 15 mins to get to home screen) that it almost isn't functioning at all. Is it just too old, a software problem, or a glitch in some part that can be repaired. I'm running the latest Lion 10.7 and it has never let me down before. The only other thing is that the sound has stopped, no input or output showing when I check in preferences.

Please don't tell me it's just got to be scrapped....