It's important to define the term "network key".. Are you referring to the password which allows computers to access the network wirelessly..? Or are you referring to a password which allows you to access the router and and make changes to the router's network settings..
Remember also, YOU should have the ability to change the network password/key by accessing the router yourself.. Do it now.. If you don't know how, then you should have asked the tech to teach you.. Or.. let us know the make and model of your internet connection and router and we might be able to help.
In addition, most home networks have limitations which block wireless access to the router's network settings.. Make sure those limitations are enabled so only "wired" connections to the network are allowed to make changes to those settings. It's much more secure that way.. Even if you use a laptop to connect to the network wirelessly, whenever you choose to change network settings occasionally, it's easy to plug in an ethernet cable to make those changes..
Hope this helps and let us know more.
hello! I have a question. Recently, there was a tech guy here at my house who helped setting up my network conenction. He even set up my network key. My question is, is it possible for him to open my connection/ or see my files just by having my newtowrk key?