Windows Side Bar

I have an Inspiron 531 running Windows Vista Home Premium. I just did a full recovery because it would not let me install any new software programs. My side bar now has a soild gray background with the gadgets on top. Prior to the recovery, the gray background was not visible anf the gadgets were simply on top of my wall papaer but still lined up on the right side. How do I get rid of this gray background?