Oops, sorry that didn't help. That is certainly where my file is but perhaps your's is for some reason located in a different location.
Assuming that you have a least one sticky note on your desktop and that you have taken the necessary steps to un-hide hidden files and folders as well as system files, then you may need to use something like;
Everything a faster and to some extent more robust search tool, especially if you're looking for ..... well everything. That's how I found mine.
Good luck and keep us posted.
Randy
EDIT: Just type in stickynotes.snt or try *.snt and see if it produces any results.