you find out the make and model, post that info in an online forum, plus a full description of the fault.
You say the "power button isn't working". Is anything happening at all? Is the set's pilot/standby lamp on? If the thing is copletely dead, have you checked the cable is plugged in OK (both ends)? Is the fuse OK? Is the power point live? Is the cable damaged?
XXXXX
October 2015