Solid Orange light

You might want to give a hint as to what the new hardware is...(only if it's not top secret). Little things like that can really help to know.

Lot's of people would also ask what computer make model style, etc. you have.

Solid orange light typically means bad MB, so it's possible it's the CPU.  Blinking orange would mean bad PSU.

As fun as it is to do everything at once, a good rule of thumb is to install one piece at a time and see if PC works.

Back off one piece at a time and see if that gets it working again.  I'd remove the GPU first simply because it's easier.  Still the same?  Try the previous CPU, and so on.

It would still help to know model and size of your Optiplex, what PSU was installed, what GPU was installed, as well as the CPU.

A new cpu, graphic card and power supply 

• I have the same problem too in my optiplex 380 its just solid orange/amber light (I can't post) I tried removing the gpu, cpu, ram, and the CMOS battery nothing worked but it booted one time and shuts off itself but I don't know how to fix it. Maybe removing all the components and putting it back might work because I saw it boot up but it will shut down after 5 secs so you have to be fast to press the F12 button but I haven't tried it yet

Hi @MAC5_Op380,

Change the size 2032 CMOS battery for a new one so it's ruled out.  A low battery can cause all sorts of bizarre problems.  I get good deals on Duracell and Energizer batteries from Amazon.  Sony only lasted me 2 years.

Did you do something similar to the BIST test?  It's a way of testing various components to see if they're good or bad.  Remember though, solid amber power light means bad MB.  But you might be on to something since your PC changed behavior.  BIST Test 

One trick to get into BIOS if the PC doesn't give you a chance - remove the battery.  Then it should give you the low voltage message.

https://www.dell.com/community/Desktops-General-Read-Only/ISSUES-WITH-DELL-OPTIPLEX-380/td-p/3761546 

https://www.dell.com/support/article/en-us/sln143164/dell-optiplex-system-does-not-boot-to-windows?lang=en 

Cmos battery does not fix physically bad motherboard.

https://www.dell.com/support/article/en-us/sln284978/a-reference-guide-to-the-dell-optiplex-diagnostic-indicators?lang=en#2009_to_2012

The Diagnostic LEDs remain 1, 2, 3, 4, and placed on the front of the unit.

Diagnostic LED numbers 1, 2, & 3 are illuminated. Power button LED is solid amber. A possible coin cell battery failure has occurred. Remove the coin cell battery for one minute, reinstall the battery, and restart.

Diagnostic LED numbers 1 & 2 are illuminated. Power button LED is SOLID amber. A possible system board failure has occurred. Disconnect all internal and external peripherals, and restart the computer. If the computer boots, add the peripheral cards back one by one until you find the bad one. If the problem persists, the system board is probably bad.

Diagnostic LED number 1 is illuminated. Power button LED is SOLID amber. A possible system board failure has occurred. Remove all peripheral cards from the PCI and PCI-E slots and restart the computer. If the computer boots, add the peripheral cards back one by one until you find the bad one.

Diagnostic LED numbers 1 & 4 are illuminated. Power button LED is SOLID amber. Power connector not installed properly. Reseat the 2x2 power connector from the power supply unit.

Diagnostic LED number 2 is illuminated. Power button LED is Solid amber. Possible peripheral card or system board failure has occurred. Remove all peripheral cards from the PCI and PCI-E slots and restart the computer. If the computer boots, add the peripheral cards back one by one until you find the bad one.

Let me try it

The amber light was not blinking tho just a fan noise and no display but I used my analog multi tester says the cmos battery has 2-3v volts (DC)

2.5v and below not good.

We moved past the phase just a solid amber light to the PC shutting itself after 5 seconds.  Otherwise, I still wouldn't mention battery.  I take it the PC didn't have anything lit after it shut itself off.