Today I tried to launch my Android app from within eclipse but nothing happened. Everything worked fine yesterday. I tried a few things like adb kill-server, adb-start-server. At some point I got the "user data image is used by another emulator" error, so I went about deleting the .lock folders in the avd image but to no avail.
I created a new avd and the emulator doesnt even start with this image. I tried to start it with
emulator -avd avdname
->nothing. No error. emulator.exe is running in Taskmanager.
Windows 7 Android SDK Tools, revision 7
Update: Now I know when I get the error
emulator: ERROR: the user data image is used by another emulator. aborting
it's when I try to run the application again after the emulator.exe is already dangling in Taksmanager.
Update: waited for 20mins. emulator.exe is just sitting there with 00:00:00 cpu time.
When you say, "Everything worked fine yesterday", you should first ask yourself what you have changed since; have you installed anything that could interfere with the emulator?
Personally, I would download a fresh copy of the Android SDK, remove the reference to the currently installed version from your PATH, and add the new one.
I should think that would solve your issue (at least, being able to start an AVD that is).
One more thing to note is that the AVD can sometimes be quite slow to startup. On one of my machines, it has taken up to 7 minutes to boot up. So try emulator -avd avdname, then go make a coffee and see if it works when you return :)
Good luck!