I can't play songs from nokia 7210,

Hello,


my name is anupam dolui.... i have many problem with my nokia 7210 handset.
i am facing this problem for few days.. whenever i try to play song/video it shows operation failed.... neither i can play songs from media player nor from memory card..
i can not connect to intrnt directly from my phone... but when i connect it through my computer it connects... sometime it shows no network... sometime it becomes very slow.....
i am just puzzled with my mobile... so please help me... i need it most.... i will wait for a positive reply.........

thanking you,
Anupam Dolui