Router connection

[Mamacat104]

I have two computers, both with Windows XP operating systems, connected to the internet by a router. I have a DSL modem connected to the router and each computer wired to the router. On one of the computers, I can click on the internet providers Icon and sign in with Userid and Password. On the other computer, I cannot get on that way. Which in most cases, it is okay.
I click the Internet Explorer icon and go onto the internet and when I want to read my email, I sign in with my userid and password.
But I'm running into a problem...if I try to update something, try to send an email from a website, it brings up my internet providers sign in screen and wants me to sign in. I cannot sign in...everytime I try, it fails. I have called my internet provider and they say they don't know what setting I need to allow me to sign in and to call Linksys. I had a person at one time on the line at the internet provider that helped me get two computers set up and they both were able to sign in...but I changed computers - upgrading to a faster one and one with windows XP, but cannot get this one to sign in to the internet provider itself.
I have found that I need this capibility now and then. Any idea what I can look for, a setting or something that will allow me to sign directly into my internet provider?
thanks
Barbara

[Spider]

Open the Linksys interface (http://192.168.1.1)

You'll be on the Setup(tab), go to Wan Connection Type and change it from
Obtain an IP automatically to PPPoE. Put in your username and
password.

Your ISP should have told you your on a PPPoE connection. They failed you not telling you this.