MacBook Air keeps shutting off

Hi,

Today I was syncing my iPhone up woth my MBA, while doing so the screen went black. I thought it was the same thing that was happeneing to other people with MBA's where the screen shuts off and then turns back on after a few swconds. However, this wasn't the case. I waited about a minute or two and just pressed the power button, when doing so I heard the power on sound and my MacBook powerwd on. Now this has happened to me a total of 5 times in the span of just 15 minutes and it is only while I am in iTunes. It's open in the background right now and it's fine, but when I go to play music my computer shuts off.

Could someone please tell me how to fix this??

Thanks,

Hunter