file extension 1-windows[1]

The 1 at the end signifies that it's a duplicate of something already there or that was already there at some point. I would uninstall it or otherwise delete any entries pertaining to it.
Have you been running any registry cleaners lately? If so stop as they can cause this sort of anomaly.

I've never heard of a file extension like "1-windows[1]". Apparently Windows doesn't know what to do with this file, because Windows looks at the file extension and decides how to process the file. Almost always, a file extension will be three or four characters (something like .docx or .exe). If it is .docx, Windows will open it with Word. If it is .exe, Windows will see it as a program and try to run it.

Right-click on the file and choose Properties. On the General tab there is a filename window at the top. Also, right below that it shows you the Type of file, and the program it opens with. In both of these places it should show you the file extension. What extension is showing there? And what does it say that the file will open with?

If you know what kind of file it is, you can add the correct extension onto the end of the name -- put it in the filename window at the top of this screen, then click Apply at the bottom. That should fix it.

As Samuria said above, it could be malware. If you aren't sure about it, run an antivirus scan on it.

This also may help: Default File Type Associations - Restore - Windows 7 Help Forums
Also check for malware.

OK good luck ;-)