Help wiping clean and reinstalling OS X on used Mac Pro

[3fingerbrown]

I just bought my first Mac, a used Mac Pro, the 2 x 2.66 Dual Core Xeon version. It is currently running OS X 10.5.6. I would like to wipe the hard drive clean and reinstall OS X. I understand this would get rid of unwanted software, let me change the administrator, and let me set things up how I want.

I tried booting up from the install disc, by starting the computer while holding down the "C" button. It said I can't install the install disk's version of OS X because a newer version is running on the computer. My question I guess is pretty simple: How do you erase a Mac Pro and reinstall the OS? I've also heard that its better to "zero out" a used hard drive, which will help it will run faster. Should I do this and how?

The computer may also have applecare warranty left on it, should I get this transferred before reinstall the new OS is this not a concern? Thanks.

 

[kalex]

when you start your mac from CDrom you can go into utilities on top and disk utility. that will allow you to format the drive and you will be able to install it clean. just in case before you start, if you have external drive, download super duper and clone it. this will allow you to go back in case install fails.

you can transfer applecare at any time. Friend of mine bought his mac in craigslist and his HD died. he took it to apple store and they transferred it on the spot to him