I have a dell t3400 (core duo e8400, 4gb Ram...) which was powered by the oem psu, but I changed it to a corsair vs450 so I could power my gpu. Two months later, after taking the gpu and psu to another pc, I put the oem psu back into the dell, and tried to power on, but there is a blinking orange light in the power button. I doubt it is a mobo problem, because it was working today. Any ideas?
Blinking Amber power button is Bad Power supply. Solid Amber power button is Dead motherboard. T3400 with X38 Express Chipset
525W Active Power Factor Correction (APFC) power supply.
M1J3H, 7JVXX, D525AF-01
PSU may be bad or USB Ports may be damaged creating a short on a main power rail. (PS_ON asserted, PS_PWRGOOD not asserted)
Did you leave something disconnected? I have a similar T3500 (Xeon W3670) workstation. I've had to double check myself a few times when disassembling/reassembling the machine.