Power Mac G4 won't boot HELP

I have a Power Mac G4 gigabit dual 450. Recently I removed my hard drive in a an attempt to move all my MP3 files from my PC to the Mac. Needless to say I failed in doing that however once I reinstalled my hard drive back into the Mac I noticed when I try to boot that the Apple logo will appear momentarily then it is replaced by a cancel icon. I rebooted, holding the option key I believe it was, and checked to make sure the hard drive was being picked up. Anyway, doing that showed two arrow keys with a picture of a hard disk in the middle that said Mac OS X 10.3.9 in it. I selected the drive and clicked the arrow to allow booting to began only to see the same results with the cancel icon again appearing. What the heck is going on?!

What did you do when you put the drive in a PC to try and add your MP3's? It sounds like whatever you did messed up the OSX install. Do you have the 10.3 media?

As dtravis states something in the formatting has changed and the Mac cannot recognise the drive. Did you do anything that may have partitioned the drive? Pop the Panther install CD in and reboot holding down 'C', go to Utilities and hit Repair Disk.

If all is well then reboot. Otherwise up for an erase and clean install.

harry, thank you for the advice because it fixed the problem