Well opening it up would be my absolute LAST resort as it completely voids any chance of a warrenty and unless you possess some impressive electrical skills, you could really screw some stuff up.
First off, it this iPod covered under any kind of warrenty (AppleCare, store you purchased it at, etc.)? If so, definitely call them and arrange for a pickup so it can be repaired/replaced.
If not, give
THIS SITE a good look and try resetting the iPod, and if that fails, try the Diagnostic Mode. Best of luck!
