Dead wireless - help!

[Tak]

Ok so tonight while getting stuff from the network, I noticed a computer listed that was not any of the ones in the house.

I told Mic and we attempted to change the password on the wireless settings of our router - a linksy wrt54g.

Both of the pcs are wire connected so it is only the likes of phones and lappys that use the wireless.

When changing the password, the management page tells us it is all saved etc but none of the wifi items can connect using new or old password (we checked old one just in case).

We did a factory setting reset but the end result is the same - the password changes for the administration program but not for the wifi (even though we are putting it into the "wifi password" option).

We have turned mac address filters off so it isn't that.

I have sat here and stared at the settings and options and I can't see what has gone wrong - literally the only thing we did to start with was (successfully within the admin program) change the password. It is just the wifi access that seems to be dead/blocked/annoying me on purpose.

(oh and remember to talk idiot language - it may be me trying to sort it out so it will save stupid questions later )