Q: I forgot my admin password and don't have the cd

Resetting or changing a password:

For Snow Leopard or earlier:  http://support.apple.com/kb/HT1274

For Lion or later:  http://support.apple.com/kb/HT6022

If you are in the US call Apple Customer Support 1-800-767-2775, provide the Serial Number and specifications of the Mac, and for a reasonable fee, they will supply a replacement set of system discs (if available).

The discs will be for the original version of the OS that was pre-installed when the Mac was manufactured.

If you are in another country:

http://support.apple.com/kb/HE57