Failed Leopard Snow Leopard upgrade, Macbook refuses to install OS.

Question

I tried upgrading a MacBook (version 4,1, 2.1GHz, 1GB RAM, Leopard 10.5.5) to Snow Leopard using the retail disc (10.6.3). The installation failed (with one minute remaining, naturally) and now I can't install any operating system on the MacBook. Installation fails using the default discs that shipped with the computer, and the MacBook fails to boot to the SL disc.
Any suggestions?

Answer 1

Thanks for the feedback. That's good advice. Here's my standard.
Get a bootable, external HD (preferably FireWire, since it's 40-50% faster than USB 2 and designed for data transfers), make a bootable backup/clone before updating/upgrading, and ensure that it's bootable and works like the original. That allows you to revert to the previous good state without having to reinstall or reset anything. See these for details:
http://docs.info.apple.com/article.html?artnum=106941
http://www.macmaps.com/upgradefaq.html
http://www.macmaps.com/backup.html
http://www.thexlab.com/faqs/installswupdates.html
http://www.thexlab.com/faqs/backuprecovery.html
If you only have a Time Machine backup, ensure that you can reliably restore it to another disk/volume/partition before updating/upgrading.
Good computing.