i have a problem with my dvd head unit (plz help)

[TY318]

hey everyone
i have a head unit that plays mp3 dvd....blah blah blah the problem is the volume wont turn up or down i tryed the remote and it dosnt work either its a normal looking head unit but theres a 7" screen that comes out i tryed finding a brand looking all over it but ??? cant find it it dosnt freez up it did work but now it dosnt wanna produce sounds and yes everything was connected it was givin to me by a guy that had his system updated to touch for free hehe anyways yer i cant figur out the problem im hopeing someone can help me i made sure everything was connected but in the end i took it out and put a $50 head unit in for now anyways
heres some pics

[TY318]

sorry there big lol didnt mean for that to happen and the quality isnt great