Intro and a Question

Hello,
My name is Steve Smith. I am an artist living in California. My work is 
is non-digital but I like to mess around with Blender in my spare time.
( My artist website: http://www.oneiricrealism.com)

I joined this group a few days ago. Presently I am not doing much with 
Blender. I had worked with it a year ago and gotten to where I was 
moving around and creating fairly easily...but then I burned out on it 
and stopped...a mistake..now I have to start all over again. I 
purchased the book The Essential Blender and plan on working through it 
at some point. It will be some time before you see any creations from 
me but I wanted to join this group so I would have a place to come and 
ask questions and learn.

My first question is this: How can I get rid of the black shadow that 
appears behind drop down menues. This black image lingers a bit in the 
buttons at the bottom when I click them and when I render. I am on a PC 
using Vista. ( I had way less troule working on a Mac) Everything works 
fine in Blender even with the black shadow,but I just hate the look of 
that shadow in my workspace. 

Thanks for any information you can give me on this question....Steve