Erasing Hard Drive?

I've just recently bought a new MacBook Pro and am in the process of selling my old one. I want to completely erase the hard drive but because of a fault with the nVidia graphics card I can't boot from the original install disk due to a scrambled screen. I've been looking for information on erasing drives and found something I hope may be possible. Using a firewire cable can I mount my old laptop onto the new one as an external drive/device and use the Disk Utility from my new machine to completely and securely erase the hark drive. Is this something I can do and if so what is the complete procedure? I've never used external drives before.

Just had an additional thought... would it be possible to connect up with a firewire, load the Tiger install disc into my new machine and erase and re-install the OS onto my old mac?

I believe you're referring to Target Disk Mode. Read this Apple KB article.

Regards.

As to your second question - NO. If you try to use the Tiger disk in the new MBP it will not load. If you back up your new MBP and installed Tiger on that, then i think you could use Tiger disk to load onto old Mac. If you had another Mac with Tiger on it then u could use Tiger Disk in that Mac to load onto another Mac thru Firewire.
Hope that is clear ;D

The old mac is all okay to be a target disk. If I wipe the old Mac's drive from my Snow Leopard mac using Disk Utility (via Target Disk Mode) and select the format as Mac OS Extended, will the result be a Snow Leopard format because of the fact that Disk Utility has been used from a Snow Leopard OS? Would it be the same as if I'd booted from a Snow Leopard OS disc and used the Disk Utility from the drop down menu to erase and format the drive?

Given that you want to put Tiger on Old mac then i would start it in Target mode connect it to New Mac - Start new mac and pop in Tiger disk and hold C key then once it has booted up off Disk use the disk Utility on Tiger disk to do the erase and then quit disk utility and do the install while booted off the disk.
No - just realised that the New Mac may not let you boot off Tiger when it is already on SL. So u might need to find another Mac with Tiger on it then try the sequence.

Thanks for the help. I've got to get myself a firewire cable now Cheers!

Can't get a firewire yet but have got a Snow Leopard install DVD instead. I've been able to boot from this and through Disk Utility erase the hard drive. I chose the disk icon right at the very top of the selection window and did a 7 pass erase of the entire drive. This is still in progress. Will this completely and securely erase the whole drive? On a previous erasure I ejected the disk and restarted and was given a flashing folder icon with a question mark on it... what does this mean? Still can't boot from Tiger because of the graphics problem, but will this whole process get rid of any trace of files on the drive before I return it to Apple and would I be abble to leave it wiped with no OS at all on it before taking it in?

Phew!!

yes, it sure will erase it - the flashing folder with question mark is only telling you that the computer cannot find an OS to boot off.