There was a thread started back in end of Jan - mid Feb that dealt with
users running Outlook in x64 not being able to change their "new mail
notification" sounds. I'd been having the same problem but I found a
solution.
I had the same problem as Chris LeFebvre - I could config a sound to
play in Control Panel > Sounds. The sound would test fine in CP but
then within Outlook it would just kinda honk at you no matter what the
sound was set to.
In all my XP > x64 adventures I've read here and there about the trials
of running MS 32 bit apps (like Office) in x64. Quick sidenote: my
first experience with this began when I noticed that my "Mobile Device"
(pda) used to be under "My Computer" in XP but was missing in x64 (if
you need a solution to this, email me). Without getting overly
technical, problems arise when Office (x86-based) tries to access
libraries, sounds etc from the new OS (x64-based).
Since x64 still has areas that are x86 compatible (hence the "Program
Files[x86]" vs "Program Files" on your C: drive), the secret to making
32bit apps work usually involves pointing the app to a "32bit safe/x86
compatible" folder on your HDD - basically anything outside of the main
"Windows" folder. Think about where default Windows sound files are
located in x64; inside the x64-based "Windows" folder - a "no fly" zone
for 32 bit apps. So, to get a sound to play in a 32 bit app you have to
have the sound stored in a folder outside of a x64-based folder.
In my case I have my OS on one physical drive and my data on another,
so the solution was simple: instead of pointing the Control Panel >
Sounds browser to the same old file inside the x64 "Windows" folder,
point it to a non-x64 folder in my D: drive instead. Presto! Sounds now
work flawlessly! If you only have one HDD, don't fret, just create a
new folder outside of "Windows", name it "32Bit Safe" or some such, and
cut/copy/paste/move your sound file into it. Voila!
Happy tweaking!
Jason