I usually try just a few parts on cardboard to narrow it down. Inside the old case can be an issue so we start with cardboard, motherboard and PSU to try to power up. If those don't we are looking at the bad part or parts.
I'm building a new PC with the following components and am experiencing an exasperating problem.
Corsair Enthusiast Series 650-Watt 80 Plus Bronze Certified Power Supply
Western Digital Caviar Black 1 TB SATA III Hard Drive
G.SKILL Ripjaws X Series 16GB (2 x 8GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-1600C9D-16GXM
EVGA 01G-P3-1556-KR GeForce GTX 550 Ti (Fermi) FPB 1GB 192-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card
Intel Core i5-3570K Ivy Bridge 3.4GHz (3.8GHz Turbo) LGA 1155 77W Quad-Core Desktop Processor Intel HD Graphics 4000 BX80637I53570K
ASUS P8Z77-V LE PLUS LGA 1155 Intel Z77 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard
I'm building this PC in a Dell XPS 630 case where the original internals have died. I am using vandal momentary switch/led's for the start button and reset button. In other words the only Dell part in use is the case and one 120mm fan.
When I power up the unit the only thing that happens is all or most of the fans run at high speed for a few seconds and then the system shuts down. Occasionally the fans will run a bit longer and slow down but the system still shuts down. The MB speaker never beeps and there is no monitor activity. The monitor remains in sleep mode. The MB status light is green and if the power stays on long enough the red memory indicator LED extinguishes.
I have replaced every component at least once under warranty (the MB twice) from the various manufacturers or place of purchase. All components are new. This has been going on for two months now and any help is appreciated.