Packard bell i media i4325 uk

hi all brought this pc a little over a month ago, ive recently noticed a strange whirring sound coming from it, i think it may be the fan, i just wondered has anyone else or does anyone else own this PC and can they say if their fan is noisy and if so its this normal, i havent opened it up yet but i will just wondered if anyone can give me their advice or opinion
tar very much