If you forget your admin password for Joomla, you can reset it directly in the database. There is no other way.

So to reset your admin password, access the database using whatever tool you normally use and/or the tool offered by your hosting provider. You'll then want to find the table called jos_users and edit the data in that table. You are looking for the row with the user name of admin. Once you find it, you can edit the password field directly.

Of course there is one minor hitch. You'll notice that the password is a bunch of random characters... certainly not the password you thought it was. The password is stored in the database using an MD5 hash. So you need to take the password you want to use, convert it with an MD5 hash, and then store that in the password field.

To convert your password go here http://www.miraclesalad.com/webtools/md5.php. On this page you can enter your password, and the page will then convert it for you.