Need Help. Connected but no Internet Access

Hi, I desperately need some help with my problem.

I had purchased my netbook about a month ago and everything worked fine. About 2 weeks ago, I suddenly had a problem connecting wirelessly to the internet despite having a strong signal and having made no changes to my configuration. It either states that I'm connected to a public network with no internet access, or that I'm connected to my Home Network with no internet access, or limited access. Two days later I suddenly was able to connect, again with no change to my configuration. However the same problem keeps recurring and I have no idea how to fix it.

I hope someone can help me with this. My desktop PC is physically connected to my router and modem, runs on Vista, has a static ip address and has no connection problems. My router is a ZyXEL NBG-417N, and my netbook connects wirelessly and is running windows 7.

Is it a router issue, or just some problem with my configuration?

Can u perhaps re-check that the security key and type is identical to that of the desktop and that it matches that of the router. I was going to suggest that - purely momentarily - you try disabling the security and see if the laptop connects but I read on this forum that Windows 7 will not connect in wireless mode in the absence of a security key (?). Does the laptop connect OK from a fixed wired Ethernet setup?

Thanks for the reply. Correct me if I'm wrong, but if it's the wrong security key then I wouldn't be able to connect to the network at all right? The problem is that it says that I'm connected to a wireless network connection but no internet access, or limited access.

I've not tried a wired ethernet setup for the laptop before, but regarding the issue with disabling security, I've just tried connecting to an unsecured wireless network in my apartment building, and I am able to connect to the internet. Does that mean its something to do with my router config?

I would verify with a wired set up first then walk the wireless keys through.
As stated, you need to set up your router and laptop to speak the same language.