A:Answer No, the headphones are passive only and do not have a volume control.
Since you gave them plugged into a pc, you need to check a couple volume sources and how well it is plugged into the computer. Since you did not specify the type of PC, I will go over both laptops and desktops.
If it is a laptop, make sure the plug is firmly inserted. Some laptops have notoriously tight headphone jacks and are difficult to get fully plugged in. Since these headphones have plugs at both ends, make sure both are properly seated. Next, check the system sound menu. In Windows, control panel, hardware, and sound. Do a test there, and then check them against another set of headphones. If that worked, check the program you are using, it may have a volume output control.
If this is a desktop, follow the instructions for the laptop to start with. Then, where is it plugged in. On the speakers? Front headphone jack, or back? If it is the speakers, their volume may play a role in the headphone volume, as well as the computer. If it is the back of the computer, check where it is plugged in. If it is a jack with a colored ring, it needs to be green.