What version of the MAc OS are you running?
First, you will need to boot from another disk, for example, external drive... Or Apple OS DVD...
Then use Disk Utility to create the backup image... If you are running Mac OS X 10.5 or 10.6, then you can just resize the partition via Disk Utility...
Otherwise, delete your Mac partition, after ensuring that your backup is good... And use Disk Utility to repartition the drive, and then restore your backup to the new partition...
First, so have both a 16 Gb partition, and a 40 Gb partition? What's on the 40 Gb partition? That will either need to be deleted or resized to free up space to expand the MAC partition.
- Grab Your Snow Leopard DVD, and boot from the DVD
- Once you have Booted from the DVD, choose continue, and then use the utility menu to start up Disk Utility.
- High light your macintosh partition's harddrive...
- MAKE A BACKUP. Choose File --> New --> Disk image from disk --> save the image on a different disk, and choose compressed image.... Let it run, until done.
- Click on the partitions, and resize as needed.
Is this a real Mac, a Hackintosh or a VM ? – Paul R – 2010-04-21T10:04:46.020