ATX PSU keeps shutting down with heavy 12v load

[mauserman48]

thansk for all your comments and suggestions, but I decided to strip the dell, The hp was working perfexctly in the desktop,the HDD was why the comp bit it.. I already stripped the hp. I just built 2 voltage doublers. using a 16.45 vac output trransformer I got 42vdc out using my first buil;d, then using diff diodes and larger caps I got 43,.78vdc.. when I tested between the 2 diodes in series I got 22.4vdc.. Looks like I can now have high volt dual power rails of 22.4 vdc posi and 22.4vdc neg.then I'll build variable + - voltage supplies.. thanks once again..mauserman48