When I started the adb program to connect to my android phone (a Nexus One), I got the following error:
Error: More than one device and emulator
The message says it all ... But I did not know how to stop the emulator (well, the "adb kill-server" command works, but the emulator starts again when I start ADB from the command prompt).
Finaly, the solution was fairly straightforward. Use the -s option with ADB to connect to the right device ..
You can find the device with the "adb devices" command.
TIP: I finally removed the 'ghost' emulator-5554 http://0bar.nl/en/tech/adb-device-emulator-5554-offline