That's odd, particularly if you hold those keys (Ctrl-Shft-~) down at the
same time followed by the letter and get absolutely nothing, not even the
unaccented letter or a space. Just a guess--is it possible you are not
using the standard (U.S.) keyboard? You might want to double check all the
settings to make sure something did not change somewhere along the way. I
have been using the keyboard to type international characters for years and
through several iterations of Word on many different computers. But on
occasion I have switched Word to a international keyboard (in my case
German--trying to switch Word keyboards in German is a big mistake! Same
old keyboard and keys but sooo many are switched around that you will never
remember which is which!) and the keyboard shortcuts no longer worked,
perhaps because the specific int'l keyboard already includes those very
characters! Anyway, just a guess.
There is a great MVP paper on this at
http://www.mvps.org/word/FAQs/General/InsertSpecChars.htm.
See KB Article 269750 for other details, including references to the Visual
Keyboard. Note that this may be for Word 2000 but it works in later
versions as well.