problem with my ebay powermac

I recently recieved a Powermac G5 1.6ghz from ebay. When i recieved it i was clearing the stuff on that and was transfering my files onto it. During my little adventure it froze up. So i proceeded to restart and upon starting it again it took FOREVER to boot and when it finally did it took way too long to go into tiger, then the top right hand corner stuff (airport clock ect) never loaded and i am unable to click anything and just have the little rainbow pinwheel going.

help

It is ALWAYS a good idea to wipe the drive and reinstall the system on a used computer.
You never know what the previous owner did to it or what's on it.
Also makes it easier to troubleshoot when something goes wrong.