Hi - Sorry to say, you do need to replace that PSU. Hardware Secrets reviewed the 450w version
and it could only deliver 240w! They referred to it as "a piece of junk that can damage your computer"
Do you have a budget for a new unit?
ATX-TL450W-BK 450 Not 450 watts. Can only deliver 240 watts. Ripple and noise suppression out of spec. No required filtering coils in secondary. No Efficiency. Only one SATA power connector and no video card power connector.