If the battery is fully charged then the icon will disappear by
default but it can be changed - type battery into the dash and you
should get the relevant application to change the way this works to
always show the icon.

As for sound - question is whether sound is working or not ?

I still have a nagging problem running 12.04 LTS on my eeePC901 netbook: When I
log in, the battery-state icon, and the audio-volume icon, are visible in the
bar at top of screen. But after logging in, they are gone. The absence of
these convenience features is a real nuisance.

I have tried just about everything I can think of to get those two icons back,
with no success. One gentleman here on the list had some suggestions, but none
of them worked either.

Anyone have any ideas about what is going on here?

Thanks aplenty for any help.

I have the same netbook, but am still running 11.10. I will try to upgrade
and see if I can duplicate your problem.