With the retirement of the Openfire IM server, you no longer need to use Pidgin.
To prevent Pidgin from loading when you log into Windows, follow these steps:
- Right-click on the Pidgin icon in the system tray, choose Plugins
- Scroll down and click on Windows Pidgin Options, click Configure Plugin
- Uncheck Start Pidgin on Windows startup, click Close
- Right-click on the Pidgin icon in the tray again, and choose Quit