Turning on the powerstrip to my Optiplex GX260, the power light blinks yellow (amber). Pressing and holding stops the blinking, but it goes back to blinking when pressed again.
Many folks have had this problem. Diagnosis is made harder because this model lacks the ABCD indicator lights on the back (Note: I recently noticed that it actually does have the ABCD lights. I'm not sure how I missed them when looking for them before). Some folks had to replace their power supply. Some had motherboard issues. The following link (and maybe one or two others) implicated a USB port. Those folks had actual bent traces in their USB sockets. In my case, I just had to move my JTAG adapter to a different port. It seems like after the equipment move when I plugged everything together I had changed which USB socket on the back I was using and one of the USB sockets on the back is somehow bad.
The USB case:
http://www.randomfix.com/2007/04/19/dell-dimension-%E2%80%93-flashing-orange-power-light/
A guy who had to replace his power supply:
http://forums.computing.co.uk/showthread.php?t=140031
