Can a "wireless" modem be proteted from others using it...???

After over a year of putting up with really bad service from the ONLY "high speed ISP" in my area, we went back to the local phone company's service. The phone company's standard 3M service is so superior and sooooo much faster then gowisper's 6M service it was jaw dropping, and I would never have believed it if I didn't experience it.

My question is this:
Is there a way to stop someone, in the same location, from accessing and using the new service...???

The connection consists of a "wireless modem" connected from the phone jack and then my PC.
The "wireless modem" is a COMTREND Wireless ADSL2 + Router.
There are 4 Ethernet connections, and presently my printer and PC are connected. I do plan to use a third slot for a camera system.

there will be setting in the router ,usually accessible from your browser.
in your case i dont know the way as im not familiar with your isp or router,
in my case i have a BT home hub manager in my bookmarks, once open in the settings window i input my password and adjust the settings, including turning off the teenagers wifi access when they get in trouble.

oooh im mean.

It was a pure physical connection and instantaneous. No software included.

edee said:

First gain access to your router through you browser, most routers use the ip address http://192.168.1.1 , if you have never gained access to it before and it is a brand new router, it is going to ask you for a user / password , on new routers it is usually admin / admin ( I would suggest changing this once inside the router ), if it is not, consult the manual you got with the router.

Not knowing what type of router this is , once you are signed in there should be a security tab, it is on that tab where you can select whether to have a secure or unsecure connection. If you choose secure, make sure to write down the passkey EXACTLY as it is shown, you may need it in the future to gain wireless access with another device. A secure connection will keep others out that do not have the security key, don't give it out and others won't get in.

Again MAKE SURE you change the default username and password before signing out, make a note of it and store it with the wireless security key.

That page comes up on its own every once in awhile......spooky.
Anyway, went there and evidently it has an assigned password and login already.
Called the weekend tech and she is issuing a TT to get me the login info or to make it secure, which ever comes first. Probably Monday before I know.
Thank You.