next time this happens, you can reset the password manually by holding down the reset button on the router as you plug it in for 30 secs.
the other route, i'm unsure which router make you have, but I have a dlinks, and you can take your lappy, hard connect it to your router, and type in the address
http://192.168.0.1/
this brings you to a page, I don't believe you need to place a name or password on the first page 'Admin' for the user 'Admin' for the paswrd sometimes, then login, first time i did it, i just hit the log in.
in the next page you come to where you can reset everything with no password
once in, put a password, make a copy of it when it tells you and save it somewhere you can find it. use as mentioned about a WEP as its secure, and you don't want to be having people leech off your system, it slows you down and for other reasons.
glad you sorted it out.