How do I delete Marketpress and completely start over?

Ok, I admit that somehow I completely messed up and now the store will not show up.
I deleted all the files off of my server and then re-installed, but that didn't work.
Did I miss where some installation files may be hiding?
Please help!
Thank you very much!!!

Cris
*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
Edit:

My installation is fine. However when I change the permalinks, that's when the store pages refuse to show up. I have followed the instructions step by step and I still cannot get the store to load up. It connects to a "under construction" page. I have changed the presentation page and resaved numerous times and the store page refuses to load.

What in the world could I be doing wrong?