Problems With The Volume

I have volume on my netbook but it's very faint volume. I don't see the Volume Control on the taskbar, but when I go the control panel to add it as an icon, it says the the Volume Control Panel hasn't been installed so I can't add it (the volume control) onto the taskbar. It does say to go to the Add/Remove Programs to install it. I went to the Add/Remove Programs but I can't find it. Yesterday was the first time using the netbook in eight months. I sent the netbook for repair sometime in late April 2013 because the screen wasn't working. Everything is intact now except for the volume, I don't know why that is. I wonder if the fact that I haven't it used the netbook for a long time has to do with the volume not working. I dont think so because everything else works. I tried a full scan using Malawarebytes and it didn't detect any malaware. I did a partial scan and didn't find any viruses. I tried System Restore twice but that dosen't work either. My brother thinks I need to reboot the whole computer. I think I might have to install something, but I want to hear other opinions first.