Sorry for the late reply.
Step 1
Play a disc you are sure has worked before. If it does now, there is nothing wrong with your player.
Step 2
Check the non-playing disc for scratches and dirt. If the disc is damaged it may not play properly.
Step 3
Make sure the discs you're using fit the correct format specified by your DVD player. For example, if your DVD player doesn??t support DVD-R's, then you can??t use such a DVD.
Step 4
Clean the laser lens with a DVD laser lens cleaning disc.
Step 5
Insert a correctly-formatted, undamaged disc into your player. Listen to see if it begins to read the disc. If it continues to make no sound and gives you the same message, then the problem is probably that your disc is not spinning in the device.
Step 6
Turn the device off and unplug it. Take off the outer casing by removing the three or four screws and lifting the top piece off. This will allow you to see if anything is simply stuck or jammed. If this is the case, a simple nudge back to the correct position will fix the problem. Maybe there is alot of dust accumulated in the drive mechanism. If this is the case clean with isopropyl alcohol and a clean cloth.
DO NOT TRY TO RUN THE UNIT WITH IT'S COVER OPEN.
Step 7
Clean the lens while the DVD player is open. A dirty lens is most likely the cause of your no-disc error. The lens should be cleaned with isopropyl alcohol and a cotton swab.
Step 8
If none of this works, take your DVD player to have it professionally fixed. Onida should be easy as they have service centers in all cities.
Cheers