Hi DavidinMK. Not sure on this, thought it may be the volume Icon missing and that is easy to correct. As for the slider bar not showing, I've not come across this before but one of the forum members will have the answer. You could try this though, it may work.
Alter your screen resolution by right clicking your mouse on the desktop choose properties and change to a higher or lower rate, save and exit back to the desktop. Reboot your PC then change it back to your normal setting, re-boot again and see if this has cured it for you. j.