Kernel Panics on startup

So, i updated my leopard to the developers version of snow leopard. It all went well until the end of september. My MBP was running fine and then the screen froze up (shift in colors, got a little bocky) and gave me a kernel panic. No big deal, i restarted, and it booted fine. Then, i got another KP. I rebooted and the boot screen was much larger than normal, then the screen went to black. I reset the pram and everything was fine until it froze again a few days later and i had the same problem. I upgraded to snow leopard (a friends copy, not mine) and it has been doing the same thing. I want to just erase the HD and install leopard because it should work (i googled around and it seems that some people only have trouble with snow leopard and not with leopard). I popped in my leopard disc and cant boot from it (i guess you cant boot from older versions DVD installers). I had trouble booting with the snow leopard disk last week untill i switched out my ram. I then switched it back to how I had it and it booted fine. This will no longer work.

How do i go about erasing my HD? is the only option to boot in target disk mode with another mac? then i would have to get a firewire cable, but if it will work i have no problem spending the money. Is there a way to fix my problem? will downgrading to leopard do anything?

You've got a lot going on there...making the situation a bit complex.

Here's some stuff to read that may help you sort things out:

Mac OS X Kernel Panic FAQ

Resolving Kernel Panics

Hope this helps,

- Nick

Is the Leopard disc the one that came with your Mac or an actual retail version? Just making sure because you can't use another system's restore disc to boot/install.

If you have a USB drive (At least 8GB) you can try installing Snow Leopard on there and using it to see if you get anymore problems. If you do get a kernel panic while using the OS on the USB Drive, it probably means a system board malfunction and you have to send to Apple for repair.

I'd also try booting from the CD (Snow Leopard or any Mac OS X CD) and run Disk Utility's "Verify Disk/Repair Disk" option.

Lastly, try Apple's Hardware Test on the system.
Intel-based Macs: Using Apple Hardware Test
Good luck!