Problem with New Computers password

I just got my first Mac from a second hand store and it runs great and I seem to have no problems with it, but it is logged in as the previous owner and they aren't the administrator. So, I can't download and install anything because I don't have the password or the 'rights' to do anything without the administrators permission. How could I go about resetting the settings, or anything else, so I could be the administrator? I'm able to go about everything else, I have just been making sure not to log out to whoever the computer automatically logs in to. I don't know anything about Mac's at all, I've always had PC's. HELP PLEASE

Welcome to the Forum - First a question - did the second hand shop include the original install disk. If so power on and pop that in and when it boots of the CD go to drop down menu and select reset Admin password - done. If u are really running 10.1 i would splash out and get a later OS at least Panther 10.3 or better still Tiger 10.4. You need the disks that look like this DVD pic - not the grey ones which are model sepcific;

Click for full size

Actually no, I got no CD with the computer, and I was thinking of wiping out everything and restarting from scratch, but then I would lose all my programs as well, like word and photo shop which were on this computer. As for if I'm running OS 10.1 I'm fairly certain that's what it is. I really have no idea with macs LOL.

Well if they are on the computer and you received no discs they illegal copies anyway! Do as Collin suggest, pop your Tiger disc in, erase and format the drive to Mac OS Extended (Journalled) and do a clean install.

You will run into all sorts of trouble with no password or install disc to troubleshoot.

That's the thing though, I don't have any disk what so ever. No tiger disk to erase the drive. Where could I get something like that?

You won't be able to do anything without an install disk. If you got any Mac without one, it could very well be stolen.

To find out exactly what version of OSX you have, click the Apple menu at the top left of the menu bar and choose "About this Mac". There you'll see the version number. Then go to an Apple Store or Amazon.com and buy a retail copy of that version.

Okay I just figured out that I have a Mac OS 10.3.9

Tiger still brings about $80-$100 second hand alas. Make sure as Collin says you purchase the full install DVD. Do not buy the silver grey system restore discs as they are very much model specific. Beware sellers also offering full 'drop-in' versions.