Here is the online manual for the GX270 followed by the steps Dell suggests to resolve this.http://support.dell.com/support/edocs/systems/opgx270/en/ug/solve.htm#1236733
If the power light is blinking amber — A device might be malfunctioning or incorrectly installed.
Remove and then reinstall the memory modules.
Remove and then reinstall any cards.
Remove and then reinstall the video card, if applicable.
Toggle the voltage selection switch on the back of the computer.
If the problem persists, contact Dell.