New Computer with Live Mail

I have built a new system Win.7 and have Live Mail for E Mail. If I try to send an E Mail I get a pop up saying that I used the wrong password. After that I tried my XP computer and it wouldn't connect. I had been using it for years. I re-booted my modem and router. Then the old XP computer was ok. It seems that Live Mail is doing something to either my router or modem. Help please.

First try uninstalling email account and then re-add account. Then if that doesn't work try uninstalling Windows live Essentials and reinstall it. For what ever reason, it gets corrupted from time to time, all though rare, it does happen...it's been my experience any way.

I got it to receive mail,but if I try to send mail I get a pop up saying that I used the wrong password.