I can't erase, reboot, repartition or instal mac os x leopard on my hard dr

Question

I can't erase, reboot, repartition or instal mac os x leopard on my hard drive.
I tried installing windows xp using bootcamp. I think I accidently installed it on the same partition as leopard. I didnt complete the installation of windows xp. but leopard got deleted.
I tried to reinstall leopard. I wont let me do it cause my hard drive is partition't as a windows nt file system (NTFS). I cant repartition it either using disk utility cause for some reason its read only.
Can someone help me.

Answer 1

Do this:
Extended Hard Drive Preparation
1. Boot from your Leopard Installer Disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from theUtilities menu.
2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Note the SMART status of the drive in DU's status area. If it does not say "Verified" then the drive is failing or has failed and will need replacing. SMART info will not be reported on external drives. Otherwise, click on the Partition tab in the DU main window.
3. Click on the Options button, set the partition scheme to GUID (only required for Intel Macs) then click on the OK button. Set the number of partitions from the dropdown menu (use 1 partition.) Set the format type to Mac OS Extended (Journaled.) Click on the Partition button and wait until the volume(s) mount on the Desktop.
4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.
5. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, check the button for Zero Data and click on OK to return to the Erase window.
6. Click on the Erase button. The format process will take 30 minutes to an hour or more depending upon the drive size.
Steps 4-6 are optional but should be used on a drive that has never been formatted before, if the format type is not Mac OS Extended, if the partition scheme has been changed, or if a different operating system (not OS X) has been installed on the drive.
Quit DU and return to the installer. Complete the Leopard installation. After you've installed Leopard you can use Boot Camp Assistant to create a Windows partition and install Windows.