Hi, I'm a mac newbie. Just got a brand new macbook, plugged in a guitar to record some music and the sound went haywire. Re-started and all of a sudden I can toggle volume, but no sound. iTunes produces no sound. Neither does any website. Spent an hour talking to techsupport and tried various checks, restarts and so on, but no joy. Apparently now I have to head miles out of town to an apple store and take my macbook there, where I'll have to pay for any repairs?! This isn't why I left the world of windows! lol Any ideas or advice would be greatly appreciated.