I have installed Android SDK from 2.1 to 4.0 and i have worked with Android Projects. But now all the projects throwing exception like sdk not found… While checking SDK wizard, nothing SDK is installed. Am i deleted any files?
After Installed SDK:

But now Except tools no sdk is present
Restart your IDE then go to preferences and make search for SDk folder (i think that must be in Eclipse folder) set SDk path it will work ..
I think it happens with you because you do not specify you SDK path in preferences -> Android
hope this explanation works for you..