Reset Intel Mac Mini password

Do a google search for reset lost password in Mac OSX.
Here are two responses from such a query:
see http://www.wikihow.com/Reset-a-Lost-Admin-Password-on-Mac-OS-X
or
http://coolestguidesontheplanet.com/reset-forgotten-admin-password-mac-osx/

Both contain specific steps too long to mention here.

Here's a fairly comprehensive solution: http://osxdaily.com/2010/08/10/forgot-mac-password-how-to-reset-mac-password/

If you have the system install DVD that came with the computer, put it in the drive and restart. Immediately after the startup chime, hold down the option key. You will see a hard drive button appear on the display. Wait a little longer, and you should see one or two more buttons for the System Install volume and possibly the Hardware Test volume on the DVD. Click the System Install volume, then the arrow button. When the system is finished startup, do not start system install. Go to the File menu and select "Reset Password," then select your user name from the list of accounts shown (note that it may be the Unix shortened version of your user name, with no capital letters). Enter a replacement password as directed, then restart.

If you have no disk call apple or go to apple store and they will get you one.

If you boot the Mac Mini from the system disk and go into Disk Utility you will be a able to resent the admin password for the computer.

apple mac mini 1.5 intel core solo 60gb

Have a look at http://support.apple.com/kb/HT2622 and try item 5 resetting SMC

If you have the instal disc boot up the mac with it holding down the c key. Once it has booted up you can then go up to the menus and use the change password command. Then restart. Hope this helps.

You should read the Apple Support article on changing/creating a password for the admin account. From there you can control the other accounts. BTW a common mistake is to have the Caps Lock key on. -Ken