Wireless network problems (No APs active?)

I've got a problem connecting to the internet from a laptop.
This is the situation:
- 4 PC's and a laptop
- A KPN Experia box

The 4 PC's connect to the internet through LAN wiring.
The laptop should connect to the internet using wireless but this doesnt work. I have tried many things but so far nothing has worked.

I have tried to set IP's and many more things. I need some help to get this laptop connected to the internet. It's possible to connect to a network in the neighbourhood but not to connect to the network we have at home.

If you need more info plz do ask (and specifically where I can find the info because I'm not the best at that stuff)

 

Ya im having the same problems. Only it gets worse. Now not only does my wireless not work, but i hooked up an adsl modem to my laptop (512 kb/s) and it connects but no internet!!! I connect fine but i cant do anything past that

 

The wireless does connect to the modem but then I cannot ping the modem and it is not possible to get onto the internet... I have also tried hooking the laptop up to the router using cables (as I mentioned) but this didn't work...

 

Has anyone been able to look at my problem yet?
I have tried some things out and found that if I add all the IP adresses manually it does connect to the network, but just superficiall...
I do not know the DNS ip's I need to add which I think might be the problem.