Inspiron m600 wireless will not connect to visible networks.

Running Hardy 8.04 on Dell Inspiron m600 with Network controller: Intel Corporation PRO/Wireless LAN 2100 3B Mini PCI Adapter (rev 04) for a built in wireless card.

Ubuntu correctly installs the ipw2100 kernel module and give me a list of wireless networks in range and signal strength for each of them. I select one of them and enter my WEP key and after a while of trying to connect it fails and I'm again prompted to enter my key.

I notice when attempting to make a connection the icon that appears in the notification area telling me that is is trying to connect but neither of the gray circles turn green. On my other laptop, a Dell Inspiron 8600, the lower grey circle turns green then the upper one turns green and I have internet. That rules out the network being wrongly configured as well.

Where shall I go from here?

Thank you all in advanced.