If you are getting sound out of only one speaker then it is possible the speaker not putting out any sound is either defective or one of the speaker wires is broken. Before trying to repair a broken wire or replace the speaker, try plugging a set of earphones into the tablet and check if you are getting normal sound out of them. If you are not, try playing an alternate music source like a music file stored on your tablet or an internet radio station. If you still do not have normal sound in both ear pieces then you most likely have an internal problem with the tablet sound system that you probably need to have a profession repairman look at. If you do have normal sound then the issue is with your speaker and you could try to repair it yourself.
The most common power problem is either a defective power supply or the power cord has a break in it. If you have a volt-ohm meter you can check to see if you have voltage at the power plug. If you do not you can try to check if the power supply is putting out power by baring the power cord wires near the base of the power supply and testing them for voltage. If you have voltage then you know you have a break in the power cord wires and you can repair or replace the wire. If you do not have power coming out of the supply then the supply is defective and you must replace it.
One unique problem experienced with Android tablets is that if their batteries are left fully discharged for more than 24 hours the tablet may not turn on by just pressing the ON/OFF button. If this happens, try pressing the ON/OFF and Volume + buttons simultaneously for about 30 - 45 seconds until the tablet powers up. If this does not work, try pressing the ON/OFF and the Volume - buttons for 30 - 45 seconds. One of these combination should normally work.