Yogi,
Well, your situation does pose a bit of a dilemma, what with all the changes
made to your system as a result of the updates you downloaded. That makes it
hard to tell where the problem lies or could likely lie.
First, digital SPDIF out would typically be connected to an amplifier via
digital in for production of 5.1 surround sound, or some other similar type
sound effect. Analog out (speakers) is just what it sound like. That is,
the line out is connected to your speakers directly, but could also be
connected to an amplifier via analog in.
So, how is your audio cable connected on the back of your computer (to which
out port)? I must conclude that if your cables are connected correctly and
all settings in Control Panel/Sound are set properly (nothing on mute), then
the problem must be elsewhere, not the with settings, but likely with the
drivers.
Try reinstalling the audio drivers. Where did you get the drivers
originally? Were they on the VISTA DVD, or on the motherboard driver CD, or
did you download them? I would say, reinstall the drivers that worked for
you originally.
Anyone please chime in if you have a better idea. Let us know what happens.