IE

I would scan for viruses and spyware.

Make sure that your AV Definitions are up to date and then download the following and update them as well.

http://www.safer-networking.org/en/download/index.html

http://www.lavasoftusa.com/software/adaware/

Once you have these updated you can boot into Safe Mode and run scans to clean up the computer. If one comes up as infected clean up the infection and run the scan again until it comes up as clean and that includes your AV product as well. Once you have a Clean System you can allow it to boot normally.

The most likely cause of this problem is that someone has clicked on an icon on a web page to use this ISP as your Default ISP this used to happen quite often with Adult Sites and Game Pages as well but as I haven't been using Dial up for quite some time now I haven't seen this recently.

The down side of this is that when you accept this service you get hit with either Long Distance Phone Calls to the ISP or are on one of those pay by the second that you are connected so they work out extremely expensive for you.

Col

What have you changed that your dial up no longer recognizes you?