Sometimes volume icon disappear from Taskbar – Notification Area, that may be due to accidentally removed or hide from notification setting or may due to some new installation. Go through below post to fix it.
You can try to enable it from the Taskbar Right-click your Taskbar (bar at the bottom of your screen), select Properties, click the Notification Area tab, then under System icons, select the one that you wish to show (Clock, Volume, Network, or Power)
Try to enable this from the Registry:
Click Start, type regedit in the Start Search box, and then press ENTER.
1. If you are prompted for an administrator password or for confirmation, type the password, or click Allow .
2. Locate and then click the following registry subkey:
3. In the Details pane, click the IconStreams registry entry.
4. On the Edit menu, click Delete , and then click Yes .
5. In the Details pane, click the PastIconsStream registry entry.
6. On the Edit menu, click Delete , and then click Yes.
7. Exit Registry Editor.
Restart the Explorer.exe process. To do these, follow these steps:
a. Press CTRL+SHIFT+ESC.
b. On the Processes tab in Task Manager, click the explorer.exe process, and then click End Process two times.
c. On the File menu, click New Tasks (Run) , type explorer , and then click OK .
d. Exit Task Manager.
To restore the operating system to an earlier point in time, follow these steps:
1. lick Start, type system restore in the Start Search box, and then click System Restore in the Programs list, if you are prompted for an administrator password or confirmation, type your password or click Continue.
2. In the System Restore dialog box, click Choose a different restore point, and then click Next.
3. In the list of restore points, click a restore point that was created before you began to experience the issue, and then click Next.
4. Click Finish.
for the detail about restoring system click here.