why wont my hot water run out of my tap anymore?

my hot water in my bathroom was working fine then all of a sudden i went 2 run a bath and it starting running fine for about 10seconds then just stopped altogether now my bathroom hot water tap and my sink hot water tap wont run any hot water and my tank makes a dripping noise for a second! my downstairs sink hot water is working fine but also when i moved in my house there was a shower already in but when i turn my shower onto the hot water flow nothing comes out apart could this be connected,can someone plz get back 2 me and let me know xxxxx