It will really depend on exactly which model of iMac that you have on what options are available to you. Please post your iMac's model# so we can further assist you. An example of a model number would be: M6498. Another form of indentification would be the Model Identifier. The identifier for the same model number would be: PowerMac4,2. You can find the identifier in System Profiler (for older Macs) or System Information (for newer models).