I know this is mostly a repost from something I wrote long ago, but it's still happening in Windows 7. Apparently no one at Microsoft noticed the Ctrl-backspace behavior in Windows is very annoying.
Under Linux, Ctrl-backspace always deletes the previous word. It always does that, no matter what application I am using. For example: I have a long passphrase (about 10-12 characters long.) When typing my passphrase under Linux, if I get 8 or 9 characters in, then mis-type a key, I just hit Ctrl-backspace and start over.
Under Windows, this doesn't work! At login (or when unlocking the screen, etc.) Ctrl-backspace inserts a Ctrl-backspace character.
Yet in other Microsoft apps, Ctrl-backspace works "properly", and deletes the previous word. It works that way in Microsoft Word, Microsoft Powerpoint (but not Microsoft Excel), and Microsoft Internet Explorer. In Notepad, Ctrl-backspace inserts a Ctrl-backspace character - but Wordpad works "properly".
These are all Microsoft apps, but they don't act the same. Why the inconsistent behavior!? How confusing!