Like most new users, I jumped the gun and didn't fully comprehend Lightroom's file management/editing system before I started. As a result things are very disorganized. I keep all of my photos in a folder on my desktop called "photos". I'd like to start from scratch and clear my lightroom catalog and clear all imports and then re-import all the raw, non-edited photos. Is this possible? If so, how? Thanks.
Yes, it is certainly possible. Using the menu, /file/new catalog/
The real question is how bad are things really organized?
While a "photos" folder on your "desktop" is not a great idea, moving that one folder to a better location is a really simple task:
Using Explorer/Finder, drag-n-drop the "photos" folder to a new location.
In LR, go to the Folders panel, right-click on the now missing "photos" folder, and do a "find missing", navigate to the new location.
Now, if your "photos" folder contains 1000 images, when it should contain subfolders, then you do have a need to reorganize.
Agreeing with ManiacJoe
You could simply use the tools available to become better organized, rather than starting all over from scratch and losing whatever work you have done so far.
In particular, you need to use keywords and other metadata as your organizing tool. By adding keywords and other metadata to your photos, and then using them later to search for your photos, it simply doesn't matter what folder the photos are in, or where in your folder hierarchy the photos are.