Problems re-installing Tiger ... am I lost?

I've been trying to do a clean install with my orginal Tiger OS on my 2007 MacBook Pro and have encountered a real problem. I can barely relate this (showing my complete foolishness), but I downloaded a copy of Snow Leopard to try it out as I was pondering whether to use Ubuntu amongst other OS. It installed just fine and easily convinced me to stay with Mac. So I bought my new laptop last weekend and listed the old one for auction (and sold it). On trying to re-install my original Tiger OS there is a problem - Disk One goes in fine, it all is great until it prompts to restart and then once restarted the screen is chopped up in diagonal zig zags making it impossible to proceed. Random clicking doesn't get me far! I've run Tech Tools and there is no video RAM faults. I just don't know what to do now. I have a couple of weeks left on the Applecare but I'm a little worried about going in to the store with this problem. Would what I've described indicate to them that I've downloaded the OS? I know I've been an idiot, but does anyone have any suggestions?? I've already emailed my buyer telling him to cancel the transaction ... hope he's not too miffed.

Welcome to the Forum. Try booting of the Tiger Install disc and once past the language selection get Disk Utility from Menu Bar and erase the disk then try your install.

Thanks for the reply. I have tried booting from the install disk, but to no avail. I am getting the same result of a chopped up screen image. I can click on things in the window but can't really read the results, so it's 100% haphazard. Not sure what to do now. Would it be possible to erase the disk completely before installing the OS via the Tiger disk through the disk utility? As I said, I can't read the screen once I've booted off the install disk, so I can't select Disk Utility from the menu bar.

Is this the Tiger DVD that came with your Mac from the factory? If not, that probably is the issue.

Would using Disk Utility to wipe the drive from the disc then allow the installation of the OS from the original discs that came with the computer?

These are the original disks I got with the computer. I have tried to use the Disk Utility from the install disc prior to starting the install process, but am told basically that it's an old version that won't work with Snow Leopard. I can't get to the Disk Utility from the OS disks after restart because of the original cutting up of the screen image. I was hoping I could wipe the disk before even loading the disk. Any ideas? Thanks for the replys so far guys!

You can purchase other software to wipe the disk. The question is whether or not your computer is capable of running it now with the problems you're having.

I've been doing some research and it seems that it is a fault with the graphics card, Apple made a statement about it earlier this year. They will replace faulty cards up to three years from purchase even if your MBP is out of warranty. The trouble for me now is that if I take in my laptop for repair, will they be able to detect that I have downloaded the OS (I restate I only did it to compare OS before upgrading to a new machine!)

Just in case;
Apple Extends MacBook Pro NVIDIA GeForce Service Policy to Three Years

And they may well be aware you pirated Snow Leopard. Maybe your problem is there somewhere.

Any idea of what the reaction would be if they could see it was bad software? How does Apple wipe a hard drive anyway? Maybe I could somehow wipe it myself? See how ignorant I am on these matters!

Will it start in Target Mode? Power on and hold T key. If that is go - you should have a firewire symbol on screen - then connect to another mac and use Disk utility on other mac to erase the Disk of the MBP. Then start over with the install.

TechTool Pro is one utility suite that I know includes a Wipe routine. I'm not sure if Drive Genius does or any other commercially available app. But I'd think you could turn up those that do with a simple search engine query.