Can not find access point

mnlemmon

What do i do...
Im not a computer tech person.
I found mynetwork key.. My ip addy... I know im using an aris router through insight digital broadband... They had someone come and install it. I being dumb through the manual away. We tried connecting a month ago and it connected fine and only problem we had was it saw our router but we didnt know our password.. Now it wont even detect it.. Says theres no access point... I read that maybe we need to change the security options.. My question is how do i do that. What do i do to find my router on my comp.. How do i change it... What do i need to do? Any ideas for any of it...

I know i have wireless internet....