I purchased my iMac with OS X Tiger over a year ago. My number pad did not work and I assumed it was a bad keyboard. However, since I rarely use the number pad I didn't care. It wasn't until I created a separate profile for my wife did I realize that there was nothing wrong with the keyboard - the number pad works just fine under her profile. I have played around with the Keyboard and Mouse screen too. Another thing that I find odd is it is just the numbers and the period that do not work. The Enter, +, =, *, - all work just fine. Today, I purchased the aluminum wired keyboard and am still having the same issue. I have tried pressing the clear button to see if that works similar to num lock on a Windows keyboard, but that doesn't work either. I have scoured the internet for a while now and have not found any thing helpful. If anyone can help me I'd greatly appreciate it. Thanks.