Admin password problem.

I have been given a beautiful Fully loaded iMac instead of payment for my contract services from a company I worked for but went belly up. Unfortunately they did not give me the admin password to the computer and the guy who computer it was at the company is long gone and I cannot reach out to him for it. There is a ton of applications on here I want to keep so I do not want to wipe the drive as some have suggested. I do have the 2 OSX install disks that came with it...it is runnng OSX 10.4.10.....I can't even back it up ( I was going to use Super Duper) and then wipe it and reinstall stuff. That has been suggested by some friends....but I do not have the original software install disks. Who knows where those went when the company dissolved... I am not too Mac savvy but I have been using macs over the years. I have never done a full back up before. I know you need to partition a drive or something like that? I want to save the applications ( it has final cut pro on it which is really expensive! ) and I need to update a bunch of stuff but it wont let me do that either...kind of dead in the water.... Anyone out there know how I can make it so I can get around or get rid of the admin thing?

If you have the 2 DVDs that came with the Mac one is probably the Application Restore disk.

My advice is to use to Boot of the DVD "C" key down and use the Password Reset option on the Menu.

NOTE: This is not the Firmware Password, don't go near that it leads to grief.