Here are possible reasons that your DVD is not booting your Mac.

Older DVDs will not boot more recent Macs.

Verify that the operating system printed on the front of your TechTool Pro DVD is higher than the operating system that came on your Mac.  Otherwise, the DVD will not boot your Mac.  For example, if the front of your DVD says 10.5.8 and your Mac shipped with Snow Leopard (10.6.x), you will need a newer version of the TechTool Pro DVD.  Contact This email address is being protected from spambots. You need JavaScript enabled to view it. for instructions on updating your DVD.  A better solution, however, is to use TechTool Pro to create an eDrive.  An eDrive is a bootable partition that you can install on your internal or external hard drive that provides improved performance and functionality over the boot DVD.

The most recent TechTool Pro 5 DVDs will not boot PowerPC Macs.

If the Mac OS printed on the front of your TechTool Pro DVD is 10.6.4 and your Mac will not boot, check whether you have a PowerPC Mac (G3, G4, or G5 processor).  If this is the case, you will need to burn a DVD that is PowerPC compatible click here for instructions.