A short while back I was moving my mouse around the screen and accidentally clicked on window explorer icon on my taskbar and at the same time doing something else. Long story short...everytime I boot up I get a windows explorer window. I have looked at my startup programs and I don't see it there. It even does it in the safe mode. Help. I would like to get rid of it.

Have a look at this MSKB article;

http://support.microsoft.com/kb/228502/en-us

Post back with your results or any further questions.