From the manual:
If the power light is amber and green or steady amber—
- A device might be malfunctioning or incorrectly installed.
- Remove and then reinstall the memory modules. See Memory
- Remove and then reinstall any cards. See Cards
- Remove and then reinstall the graphics card, if applicable. See Cards
- See Diagnostic Lights
.And:
1 Green, 4 Green with amber power button:
A possible failure has been detected in a plug-in component such as a graphics riser card or memory riser card.
Verify that any required power cables are connected to the memory and graphics riser cards.