Macbook automatically restarts

I've got an era 2008 black Macbook 2.2Ghz Intel Core 2 Duo, OS X 10.6.8 and recently it's been restarting out of the blue. The last time I noticed was when I was playing iTunes.



The only recent change to my system has been plugging in an external hard drive which is where I put my iTunes library. Could this be why??

via ehMac.ca http://www.ehmac.ca/showthread.php?t=109321&goto=newpost