If you are unable to end the BUSY Agent task in Task Manager, you can try the following solutions:
1. Restart the system and try closing the BUSY Agent task again.
2. Right-click on the taskbar and open Task Manager. Look for the BUSY Agent task and try ending it from there.
3. If the BUSY Agent task is not visible in Task Manager, but you know it is running in the background, you can try closing it from the system tray or notification area.
4. If none of the above solutions work, you may need to seek assistance from an IT professional to troubleshoot the issue further.