If you have printer / device discovery switched on and the unwanted printer is detected as accessible on your network, that printer might be added to your network and would show up as a printer on your computer.
Control Panel > icon view > Network and Sharing Center > Advanced sharing settings >
Under Private (current profile)
Normally this is not harmful since (hopefully) your network is secured and only those devices you want are allowed to access your network.
Your network settings may be allowing people you do not know to access your network.
If that is the case,
Secure your network to be sure it's not being used by the people next door, for example.
Essentially, you need to make sure you have a password for your wireless network that you do not share (and is not the silly default that comes on the router). Every connection to the network should be required to use that password before it can connect to your network.
Make sure your Security Software is marking your network as Private - public network is useless to protect your stuff.
Be alert for scammers posting fake support phone numbers and/or email addresses on the community. If you think you have received a fake HP Support message, please report it to us by clicking on "Flag Post".