Unsecured Wireless Modem? How do I?

[ImnoGuru]

Hello and thank you for reading my thread.

I have a D-Link DSL-G604T ADSL2+ wireless router, that I use to connect to the internet at my house and recently found that it is unsecured. (I know nothing of wireless internet)

I also found out, that that meant anybody can use my internet from anywhere around my house and beyond. Luck be with me, so far I haven't had any problem in that regard that I know of.

My computer Desktops and Towers are connected through cables to each computer via one of each of the four ports on the D=link modem. (it varies as to whether I have 4 or less connected at any one time.)

None of the computers have a wireless card in them.

I downloaded the instruction manual for the D-Link G604T from their website and in reading it have tried to set it up so that I can make it secure.
I have never used wireless before and some of the terms used evade my understanding. So I used best guess technology. 

My brother talked me through some setup procedures, only to finally realise that I was cable connected and didn't need all that preparation and said to just tick/or untick in the box AP and save, and it should cure my problem, that together with removing the Ariel from the router. How good that is I don't know?
We discussed and accessed different areas in the D-Link set up that included Mac addresses and hexadecimal codes.
So I am aware of these things now.

Now I have some laptops that have wireless  technology and sometimes they connect and sometimes they don't, or connect but with limited connectivity.
I have played with some settings but just haven't found the correct settings to get it all functional and secure.

Can someone please help with setting up this complex situation. 

I worked out that I can name my router so that I can identify it against other networks around me that the wireless laptops find, and have succeeded in naming the router.
Primarily I would like the router set secure so nobody around me can use my connection, but I need access for the laptops as well.

I hope that I have explained my predicament correctly.

Thank you ImnoGuru.

[tmoe30]

Hello,
When you log into the router, look for WPA2 encryption.  Enable it and create a password for it.  Then from the laptops, search for your wireless router and connect to it with that password.

The MAC address filtering, disabling broadcasting and WEP encryption are all easily hackable so don't waste your time messing with those.  WPA2 is the best way to secure your network.

[ImnoGuru]

Thanks tmoe30, for your reply. I'm sorry for the delay in getting back, lots of birthdays this time of year for me.
Mate Im still trying to get my head around WPA and now I have to find out about WPA2.   I suppose it cant be too much harder than WPA

Well, safer is better. Although... these lappies are new so there's nothing on them of any real significance yet. Its not as though I use them for banking or buying things yet. So I guess there will be a day, at least I will have a chance to learn about it then before it becomes absolutely necessary.

Patio's post in another thread has the process of walking through a setup, step by step.
Thank you patio as well for that. ( I'm actually beginning to understand what I'm talking about now)
As you stated tmoe30 the WPA2 is better, security wise and I guess I just may as well use that for all my connections to the network.

Thank you ImnoGuru.