Unable to surf he internet with laptop via router

At home we have a wlan, 2 pc's connected wireless, and a laptop from my dad's work directly plugged into the router. It all has worked before but now my father has been to work some things have changed and the laptop refuses to surf the internet.
I can get to the configurationpage of the router and that's about it.
Laptop specs: IMB Thinkpad Pentium 3 700MHZ, 128MB RAM
Win2kpro installed
Router: Siemens Santis 50, ADSL

Everything is ok, the laptop receives its IP-adress from the router, DNS settings are also correct, IP Sec is disabled, there is nothing wrong with the browser settings so I don't know what's wrong. First I thought it was the firewall that blocked outgoing connections but when I disabled it I still couldn't get to the internet. It's a bit strange because my dad uses that laptop to work at home in the weekends, so when he connects to the server it's heavily secured.

Is the default gateway on the laptop pointing to the router?
Is NAT still enabled on the router?

If you can ping everything on the network, and you get your address via DHCP on the router...

You might want to check your browser settings. Some work places use a proxy and configure it via group policy, IEAK or even manually...

In IE:

Tools, internet options, connections, lan settings

make sure only "automatically detect settings" is checked off. (uncheck use proxy)

Also make sure you are getting the DNS addresses from the router.

if you go to a command prompt and type

c:\ipconfig /all

it will list your ip, netmask, gateway and dns. (amongst other info)

They should be similar to another working PC on your network, and only the ip should be different. If this isn't the case... try to set them manually to see if that resolves your problem.

Default gateway is pointing to router, NAT is enabled
phisphreek80 That was the first thing I did: ipconfig /all and everything was correct.
Browser settings are correct.
The IP retrieved is corrrect, all IP-adresses within the lan are 192.168.1.*
The laptop is the 3th pc connected so it receives 192.168.1.4
When I disable obtain IP-adress automaticly and manually type 192.168.1.4 it also doesn't work.

just as an off the wall thought... have you tried resetting the router lately? I've heard tell that some routers occassionally need to be reset but I don't know if this will apply to your particular model. You haven't said if the other 2 pc's are able to surf the net - are they?

Z

I could still surf the internet with the other pc's but resetting the router helped!! Typical, the solution is often something simple. Thx

cool, glad to hear it's sorted. Always try the simple things first! :)

Z