Time Machine - Removing Old Backups

You should be sure your TM backup drive has been partitioned GUID and reformatted before initiating any new TM backup for your new computer. I would do the following:

Extended Hard Drive Preparation

1. Open Disk Utility in your Utilities folder.

2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Click on the Partition tab in the DU main window.

3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, set the partition scheme to GUID (for Intel Macs) or APM (for PPC Macs) then click on the OK button. Click on the Partition button and wait until the process has completed.

+BTW, this is the Tiger forum. TM is not available in Tiger, so please post Leopard related questions in the appropriate Leopard forum. Thanks.+

Do you mean for my formatting instructions or on the keyboard? The latter is labeled Option and is to the immediate left of the COMMAND or APPLE key. If you meant the former the button is labeled in the dialog.