Accessing the "real" administrator on XP Pro

I just got a surplus computer that was used (but no longer)at a company and it was networked. When I log onto the admin. account with the password given to me by the company it still will not let me make adjustments to the desk top etc. When I went into safe mode I could see that those options had been turned off by the "Real" administrator. How can I delete that administrator and become the only administrator so that the computer will be of some use to me?

Not sure if you can do this in safe mode but:

Right click my computer, then goto Manage

+ Local Users and Groups
Users


Right click on your 'Admin' account > Properties
Then goto Member Of Tab
and Add 'Administrators'
Remove anything else