I just buy a new motherboard, CPU, RAM, HDD, and GPU (basically, I bought all the hardware, but I didn't replace my PSU). I want to know if I have to replace my 450 W PSU. Here is my computer's specification: mb: ASUS P5LD2-X/GBL, CPU: Intel E8400 @ 3.00 GHz, RAM: 1 Corsair DDR2-667MHz-2GB, HDD: 1 Seagate 250GB-SATA, GPU: NVIDIA GeForce 7200GS.