Windows Sticky Notes isn't made for backup, but these alternatives are
At first glance, Sticky Notes seems like a handy little program. With a few keystrokes and mouse clicks, you put virtual Post-It notes on your screen and write whatever you want in them.
Sticky Notes keeps the text of those notes in a single file hidden deep inside your AppData folder. Here's the catch: Your backup program (and I do hope you back up) may not catch that folder unless you know enough to change that setting.
That's not the worst of it. When you close a note, the program deletes it--and everything you typed into it. Would you use a word processor that deleted your document when you closed it
[Have a tech question Ask PCWorld Contributing Editor Lincoln Spector. Send your query to answer@pcworld.com.]
Now that I've convinced you to stop using Sticky Notes, here are two much better alternatives.
Stickies
This free program by Zhorn Software takes the basic idea of Sticky Notes and does it right. If you close a note with information you need to keep, you can launch the Manage Stickies program, where you can read the note and/or restore it to the screen.
You can also control where Stickies stores its data. I recommend putting it in a subfolder of your Documents folder. That way, it will certainly be part of your regular backup.
Stickies has other cool tricks. For instance, you can attach an alarm to a note. Even if the note is closed, it will pop up again when the scheduled time arrives. And you can attach a note to an application or data file (such as a document or photo). The note will appear only when you open that program or file.
OneNote
If you're using Microsoft Office 2010 and 2013, you've already got Microsoft's excellent note, outline, and general information program. If you don't, you can you can download the limited free version. But be warned: The free version won't let you save your files locally--they can only go into Microsoft's OneDrive cloud service.
Once the program is installed, you can bring up a small quick-note window by pressing Win-N, even if OneNote isn't running. This isn't really a sticky note, but you can resize it and move it to any part of the screen. The notes are automatically saved into a location called either Unfiled Notes or Quick Notes, depending on which version of OneNote you're using.
OneNote is a far more powerful and versatile program than I'm suggesting here. But those quick little notes make it an excellent replacement for Sticky Notes.