Just did a computer update - something to do with improved Java. I restarted, as requested, opened a few programs and tried to print an e-mail - printer wouldn't open, wasn't being recognized, spinning wheel when I tried to open iTunes - called Apple, they told me to restart again, and then everything was fine. Something to do with the update not installing fully until the second restart. Unbelievable, but I'm not the only one who's had the problem.