Can't install after interupted install

I was trying to install SQL Server 2008 when my PC lost power. When I
rebooted, I attempted the install again, but it would fail every time. So, I
began to uninstall everything that had been installed by the original
attempt. After using the add/remove program feature in Vista to uninstall
everything, I rebooted, and attempted the install again. Once again it
failed, but his time during the "Setup Support Files" part.

I have installed and used the Microsoft Install Cleanup Utility to remove
everything that still remained. Now, the Add/Remove utility shows SQL Server
2008 still being installed, but the uninstall fails at the same point as the
install above (Setup Support Files).

I have even tried to install SQL 2005 (which installed beautifully) and then
tried to upgrade to 2008 to no avail.

I am at wits end with this and would appreciate any help in getting 2008 up
and running.