Q: My usb apple keyboard isn't working on my iMac. It works fine when I connect it to my Mac Book Pro. All updates are current. Other items work fine in the usb ports. Please help.

Keyboards on Macs have gone through some revisions. Older keyboards don't work properly with newer Macs and newer keyboards don't work on older Macs. Not knowing which ones you are using will make it difficult to troubleshoot. In Apple dropdown list what it says About this Mac. Then tell us which keybard you have (white plastic, aluminum, etc.) Is your user profile current (OSX 10.6.8)?

Which iMac do you have? The 2006 white plastic ones won't work with the aluminum keyboards without a firmware update.