For example, if you decide to replace your hard drive with something better– I like the Solid State Drives (SSDs) from Crucial-– you’ll be asked to activate Office 2011, and in that case, you’ll never be able to… because each installation of Office is “keyed” to the hardware it’s originally installed on, and that includes the hard drive, and the Activation ID and Confirmation ID will only work on that particular configuration. The reason for this could be that you’ve moved Office 2011 for the Mac to a new machine, or to a new hard drive, by cloning the drive. There’s a chance that things still won’t work. That will get you started down the right path.
Another option: call Microsoft’s general support number (1-80) and say “Office for Mac Activation Department” to the robot that answers.