Question : No wireless connectivity

Hi experts. I have a laptop computer which has spontaneously refused to connect via wireless. I have enabled SSID broadcast on the gateway PC (XP). On the laptop(Vista)  the network is found okay. I have manually entered the WEP key, but still no connection? Event log details:

Connection started at XXXXX
profile match: success
pre-association success
association fail
security and authentication nor started

Thanks for any advice!

Answer : No wireless connectivity

>>> association fail

Association refers to the process in which a wireless router eigther permits or rejects a connection. If it cant be established it can be due to a few reasons:
=> The connection is not strong enough (Meaning that to many packets are lost. This can be resolved trough moving closer to your router)
=> The WEP/WPA key is incorrect (Meaning you entered the wrong key, obviously entering the correct one solves this :) )
=> The AP doesnt allow your laptops MAC adress (MAC based filtering. Check your AP if it denies dertain MAC acresses)
=> The Driver for the NIC(Network Card) is buggy. (Install a new driver)
=> The NIC is incompatible with the AP (Some settings on the NIC might be incompatible with the AP)
=> The acces point is buggy (Hardware failure or similar, might even be a bad setting).

Now, i would first check, and then double check if you entered the WEP key correctly. Anyway, did you recently change anything that could cause this problem? The "Security and Authentication not Started" makes me think that the WEP and WPA protocol support is somehow disabled on the gateway PC. Also, did the connection always work and suddenly stopped? Or is it a new laptop (Or similar) that wont connect? If it always worked and then suddenly stopped, did you change anything on the gateway or the router?

With kind regards,
~Irial