Hi Hairyhobo
You must have changed something as these things don't go wrong by themselves, but I don't think your problem is with Chameleon.
Ideas?
Maybe boot in verbose mode and see if there's any messages to point to why it's failing?
Double check you've connected the video cable to the same video out connector of the graphics card.
You could always try booting from a backup bootable Chameleon USB memory stick or bootable Chameleon BootCD which you know has worked previously. You do have one don't you?
If you can't boot in to your system, then try booting to your backup installation. Surely you have one of those?
Failing the above, you could always boot in to your retail Snow Leopard DVD and install the OS to another HDD, or if you only have the single drive, create a small partition on your HDD and install another version of the OS there. Then boot in to that to give you a chance to fix your broken one.