This reply is late so you may already have realized the cause and solution
to your problems.
You are describing known issues with the Creative card and Vista 64.
If you do not have the latest drivers for the card download and install them
as many users feel Creative, which in my experience does not craft rock
stable drivers, has solved some of the issues.
Alas you can do nothing about the instability inherent in the Vista
hibernation/sleep modes. Hence you would be better off shutting down and
rebooting your computer then using sleep/hibernation modes.
The other issue is that in my humble experience Vista chip set drivers for
older AMD chipsets, specifically those using the now ancient 939 socket, are
terrible, awful and totally unreliable. They are not going to be upgraded
because the motherboard and chipset are obsolete.
Good news: modern and faster mobo/cpu combos are incredibly cheap.
Bad News: you will have to beg the Indian-who-took-an-American-job Microsoft
(thank you Bill Gates for that splendid bit of philanthropy) telephone
responder for a new activation code for your perfectly valid copy of Vista
if you change motherboards.