This is a rather clumsy mistake. I used this to hide the left module:

http://www.createblog.com/scripts/download.php?id=181

And am now unable to access anything in the column. I can only post new entries and whatnot. Consequently, I can't remove the script because I can't get to the Look and Feel section. In my defense, the link in that script page to access customizations is dead, but I should have checked first.

Many thanks.

EDIT: Hah. Literally three seconds after posting, I figured it out. Ignore this topic.

Closed at the request of the poster.