electrical problem!!! >.<

[luckie2hav3her]

basically it seems like my alternator isnt running, my car lags power, my battery light is on on the cluster and when i try accelerating it seems like my car has piping loose and doesnt get any power, theres also a buzzing / vibration coming from a 12v 5a fuse or relay (not sure wat its called) but its blue and its by the fuse box, this started happening out of no where and i have no idea wat it is now, i went to a junk yard and replaced that little blue 12v 5a item and it still did the same thing, has this happened to anyone?? or kno wat that 12v 5a blue thing is??? i think its for my alternator, i dunnoo heeelppp >.< thaanks