Dear all expert...asalam o alykum

i have Dell p4 system 2.8 processor, 40 hard, 1 gb ram, the problm is the fan of pc start very fastly and computr not move forward as i switch on the pc....its clreates too much noise and some time it started but next time same problm....i show this problm in shop they said in this model this particular problm is often..no solution...plz help if some on can do...thanks