How can I fix my dvd player?

I have a dvd player brand name is President. I dont know whether this is a genuine brand or not. (Its Chinese mad of course) so i am not sure whether this is is well known. I have had it for five months now but it want play cds, dvd or mp3. it always says no disk. sometimes it does not show on the tv screen.i have cleaned the inside with cotton and spiritwithout toouching the lens of course, but no change. How can I fix this? I have talked to some electronics technicians who all tell me different stories and i fear they might just make it worse than it is. Please help