回複：I have waited for 3 Years now.

Have you ever contacted FBI for status? What worries me more is that FBI says they can not find my record in their database while USCIS claims that they have submitted the name check request to FBI on so and so date.

You said you have been waiting for more than 3 years. Could it be possible that FBI some how lost your record? That would mean an endless and hopeless wait...