I use Windows 8 (not 8.1), and just yesterday, I think, my speaker control disappeared from the Task Bar. Why did this happen, and how do I make it come back? Otherwise, which is the equivalent speaker control from the dialog box that I found from the search bar?

Did you make any significant hardware or software changes to the computer prior to this issue?

When you say, "speaker control", do you mean the volume control icon Image on the taskbar? If not then, are you referring to any third party speaker control icon?

If you are referring to the aforementioned volume control icon that has disappeared from the taskbar, then you may try the following steps to get the volume icon back on the taskbar.

A. Tap or click the Show hidden icons arrow Imagenext to the notification area.

B. Click on Customize... to open Notification Area Icons window.

C. Locate the volume button and select the Behavior as Show icons and notifications.

D. Click OK.