ADB not responding. If you'd like to retry, then please manually kill "adb.exe" and click 'Restart'
Errors from ADB:
ddms: 'I:\android-sdk\platform-tools\adb.exe,start-server' failed -- run manually if necessary

Try below steps:

Close the Eclipse if running
Go to the Android SDK platform-tools directory in Command Prompt
type adb kill-server (Eclipse should be closed before issuing these commands)
then type adb start-server
No error message is thrown while starting ADB server, then adb is started successfully.
Now you can start Eclipse again.