If the option is not available from the mouse right-click menu, it looks like the clipboard paste function has stopped working, rather than the keyboard shortcut. How have you determined that the ctrl-C has copied to the clipboard?
Unfortunately, there are many possible causes for clipboard malfunction. When did it start happening? The problem can be caused by an operation that was performed or an application that was installed or used at the time the problem arose. (Not so helpful if it's uncertain just how long it has been that way.)
Do you run, or have you run any registry cleaners or system optimizers around the time the problem started? A damaged registry can cause it.
System file corruption is a possibility - you can try running sfc/scannow as Administrator.
Do you run any software that may utilize a shared clipboard - VM or remote assistance software, e.g. logmein?
Do you use Remote Desktop? If so look for RDPCLIP.EXE in Task Manager, stop it and see if anything changes.
Edited by Platypus, 12 December 2017 - 09:35 PM.