Fujitsu LifeBook E780 Guide D'utilisation page 171

Problem Possible Cause
Unavailable The computer to
network 
be connected is
connection turned off
(continued)
RF interference
from Access
Points or other
wireless networks
Wireless network
authentication has
failed
Incorrectly
configured
network settings
Incorrect IP
address
configuration
Possible Solution
Check if the computer to be connected is turned ON.
The use of identical or overlapping RF channels can cause interference
with the operation of the WLAN device. Change the channel of your
Access Point to a channel that does not overlap with the interfering
device.
Re-check your Network Authentication, Encryption, and Security
settings. Incorrectly configured security settings such as an incorrectly
typed WEP key, a mis-configured LEAP username, or an incorrectly
chosen authentication method will cause the LAN device to associate
but not authenticate to the wireless network.
Recheck the configuration of your network settings.
This only applies to networks using static IP addresses. Please contact
your network administrator for the correct settings.
165 - Appendix A: WLAN User's Guide