slow start n halt on shut down for ME

recently i fixed up a desktop with pIII800 n 128ram both at 133 MHz and a 20gig hd at 7200
but the start up always take about a minute or two and sometimes even longer
than sometimes when i try to shut down the ME it will display a blue screen and says system halted

can anyone help mi with this problem thanks a million
p.s i suspect problem may lie with my motherboard(mayb faulty)but anyone got other solutions