It's possible that you may have made a change on purpose that resulted in that black arrow displaying. However, it may instead mean there's actually a problem.
No matter how it showed up, there's usually a really easy solution.
What Does the Black Arrow in Device Manager Mean?
A black arrow next to a device in Device Manager in Windows 11, Windows 10, Windows 8, Windows 7, or Windows Vista means the device is disabled.
The equivalent in Windows XP is a red x. Read Why Is There a Red X in Device Manager? for more information on that.
If you see a black arrow, it doesn't necessarily mean there's a problem with the hardware, but instead that Windows isn't allowing the hardware to be used, and that it hasn't allocated any system resources to be used by the hardware.
If you've disabled the hardware manually, this is why the black arrow is displaying for you.
How to Fix the Black Arrow in Device Manager
Since the black arrow is shown right there in Device Manager, which is also where you enable a hardware device so Windows can use it, it doesn't take much to remove the black arrow and use the device normally.
To remove the black arrow from a particular piece of hardware (or the red x in Windows XP), you'll need to enable the device in Device Manager.
Keep reading below if you've enabled the device in Device Manager, and the black arrow is gone, but the device still isn't working as it should—there may be other things you can try.
More on Device Manager & Disabled Devices
If there is truly an issue with the hardware, and it's not just disabled, then the black arrow will probably be replaced with a yellow exclamation point after enabling it.
Aside from a device that's disabled, something else that affects whether Windows can communicate with a device is the hardware's driver. A device may not have a black arrow and therefore be enabled, but still not work like it needs to. In a scenario like that, the driver might be outdated or missing completely, in which case updating/installing the driver would make it work again.
If a device still isn't working after enabling it, you might try deleting the device from Device Manager and then rebooting the computer. This will force Windows to recognize it as a new device. You can then update the drivers if it's still not working at that point.
You can open Device Manager the normal way through Control Panel, but there's also a command-line command that will launch Device Manager.