Vista Volume (or lack of...)

Where's my volume icon gone?
Why is my powersave icon suddenly visible even when the laptop is plugged in?

This chap has some solutions >

http://winhlp.com/node/16

It's a long , detailed article which lists several solutions. If you find your system icons missing, here's the quick fix >

1. Search registry and delete all “IconStreams” and “PastIconStreams” entries (searching for the former, will find the latter.
2. Restart Windoze
3. Add them again (task bar properties, notification area > tick the boxes!)