Sometimes in Windows 7, users will experience disappearing of volume and battery icons from taskbar. All the options in Control Panel which will re-enable it are disabled as well. But there is an easy fix which works in 90% plus cases.
Here is what you have to do.
- Next step, you will have to start the explorer.exe again. Go to File->New Task and type explorer.exe and press enter.
- Now you will see all the icons again.