Connected fine to office network but unable to get internet access.
Found out that I had used last week password and it was changed on weekly basis.
Now it appears that you cannot edit or delete N800 connection manager via tools whilst N800 is connected to that particular network.
So in order to update password you would have to get far enough away from network to drop connection in order to delete or edit thus allowing you to connect to network.
Ok it reads somewhat daft but try it

You can drop the connection via the WiFi system tray icon menu -> Drop Connection.

It is a bit annoying that none of your registered connections can be edited unless the current connection is dropped - at the very least the current connection should be disabled for editing, and all other connections should allow editing. The problem is bad GUI design - there are global WiFi settings that can be changed whenever individual connections are edited.

Tried the disconnect option but then N800 searched all options and logged back on to original.
Problem being old password lets you get on to network but with bad connection and of course once on.........
At least winXP gives you the option of re entering password which Nokia did not.

Strange, that's not how my N800 behaves. Once I disconnect the current connection the N800 will stay disconnected until an automatic background search occurs (Connectivity->Search interval), or an application brings up the WiFi connection as it needs to transfer data.

I'm not really sure how you are able to connect to a wireless access point with the wrong password - that's a pretty broken security scheme they got going on there! I'm not able to connect my N800 to secure access points if I enter the wrong password/passphrase - it will fail with an "Authentication failed. Try again?" dialog. What kind of security are they employing on this AP?

Its a public access wireless network within main building behind wep security. N800 Picks up several differing private office networks.
I used password given couple of weeks ago that allowed me to link to network but no further. ie not past access point.
Going back next week and will ask for new password before trying to connect
this time. It was just so stupid at not been given chance to change password at connection..

maybe don;t save the connection. that way, when you reconnect, it will prompt you for the password.