I'm not sure what type of PC your computer is hardware-wise, but here's a guide anyways.
1. Download the ISO file for Ubuntu 10.04. (
http://www.ubuntu.com/desktop/get-ubuntu/download - make SURE you choose 10.04, 10.10 isn't stable on live USB/CD)
2. Mount Ubuntu 10.04 onto a USB drive. Instructions are on the link above. Scroll down until you see "Install on a USB drive"
3. Restart your computer, insert the USB drive, and instruct your BIOS to boot from the USB drive (Usually F12, F10, Delete or Escape).
4. Ubuntu's boot screen will appear. Choose "Run from this USB drive".
5. When Ubuntu finishes booting up, use Gparted (Under System - Administration) to remove your faulty Hackintosh partition.
6. Shut down, reboot, remove USB drive.
7. Fixed.