A while ago, I started using Firefox and Thunderbird, because I got sick of Opera's glitches. I've recently switched back, because I can't live without some of the features Opera has. The problems is, I'm on dial-up, and whenever my internet was disconnected, Firefox or Thunderbird both tried to reconnect. Most of the time it disconnects because someone is calling (I have a program that disconnects and lets calls in), and if anything interrupts the call after it is forwarded to my phone, it won't go through. Here is how to stop applications from trying to reconnect to the internet.
Step 1: Set to ''Never Dial a Connection''
Go the the Control Panel, and open up Internet Options. Click the Connections tab, and select Never dial a connection. Now programs will no longer try to connect. :D