Nobody's allowed to help you with the specifics of DRM removal. Alf will have to help you with that.
But your Kindle for PC books (once they've been downloaded to the app) should be in your "Documents\My Kindle Content" folder. If you still have trouble finding your books, then fire up the Kindle for PC application, click on "Tools" on the menu bar, then select "Options." From the dialog that opens, select "Content" on the left-hand side. On the right side, you'll see the exact path to where your current content is being stored.