Then MoveOnBoot should get the job done. Just install/run, point it to those files, and reboot again. Usually Firefox only creates one deletable shortcut on the desktop, though, so those three are curious.
I just downloaded Firefox latest version and when completed I had three new shortcuts on my desktop. Error message stated "Cannot delete file: Cannot read from the source file or disk". I also tried dragging them to the recycle bin but that didn't work either.
How do I get rid of them?