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!