Dell optiplex 330 flashing orange on the power botton

change power supply (SMPS)

An Amber blinking power button indicates a low voltage problem. This can be caused by a defective power supply or a defective motherboard. Since you replaced the power supply, my guess is that the motherboard has a problem.
Just to make sure that nothing else is causing the problem, remove any PCI cards like modem, video card, sound card, etc... Remove the memory modules and disconnect cables to CD/DVD drives. Look at the USB ports to see if any are damaged.

replace the power supply

Replace your PSU then test all leads that are attached to your hard drive sounds like a faulty lead of some sorts then
try replacing all the leads that attach to your hard drive including electrical extensions + IDE,SATA and the ones that attach from your motherboard to hard drive
good luck

http://www.fixya.com/support/r4282412-find_no_post_diagnostic_information_dell

Flashing Amber, bad power supply

Solid Amber either a bad component connected to motherboard of the motherboard itself has failed

hi Mostly the case there Might 2 Issues (1) SMPS the power supply is not working ( 2) mother board is faulty.
For more trouble shooting kindly check with support.dell.com or call them if the System is in warranty.

If the power light is flashing either yellow or orange and you do not hear any fans turn on, your power supply is defective. Contact Dell if you are still under warranty and if not, there are many 3rd party sites, like http://www.pcconnection.com, that you can purchase a new one.

Good luck to you.

The common issue related with a Flashing Amber Power Light is a BAD POWER SUPPLY. If the Amber Light is SOLID then it may be your MOTHERBOARD.

But if it is flashing repeatedly then it is your power supply, you will need to purchase a new one. Good Luck.

get a new power plug

Do you have a lot of accessories plugged in? They may have overloaded the power supply and if this is the case you will need to buy new power supplies. If this is not the problem, check to make sure that the computers have plenty of ventilation in the back. If they don't, they may have overheated and melted quite a few different components.