Hardware devices are controlled by the OS, Application and even services. Since they can completely interact with the devices, they are rebooted to make sure the operation is smooth. However, it may so happen that the device is shut down, and never rebooted. This is where you get error - An application or service has shut down this hardware device (Code 44).
It is interesting to note that Error code 44 can appear at any time. It could be during program installation, or during Windows Startup or even shut down. To resolve this, all you need to do is restart your computer and it should fix it.

However, if this also doesn't solve the problem, it could be a corrupted registry. You can use a registry cleaner to get rid of all corrupted, and invalid entries. Then reboot your computer to see if the issue was resolved.