SQL Server always logs install failures and install successes. On any of my computers the logs are stored in:

C:\Program Files\Microsoft SQL Server\100\Setup Bootstrap\Log

In this log directory there is a directory for each install/uninstall you have done.

First checkout the summary_xxxxxxxxxx_landingPage.txt for any errors. if this does not have that much info, next check out the detail_landingpage.txt

Good Luck.

EDIT: Scratch above response! Didnt notice in your first post you mentioned this directory is not to be found!