The Dell power button is blinking with amber color

You need to look at the blink pattern. It is documented in the Owners Manual and will tell you exactly what is wrong:

Power LED Diagnostics

The power button LED located on the front of the chassis also functions as a bicolored diagnostic LED. The diagnostic LED is only active and visible during the POST process. Once the operating system starts to load, it is no longer visible.

Amber LED blinking scheme – The pattern is 2 or 3 blinks followed by a short pause then x number of blinks up to 7. The repeated pattern has a long pause inserted in the middle. For example 2,3 = 2 amber blinks, short pause, 3 amber blinks followed by long pause then repeats.

...

2,1 system board failure
2,2 system board, PSU or PSU cabling failure
2,3 system board, memory or CPU failure
2,4 coin-cell battery failure
2,5 corrupt BIOS
2,6 CPU configuration failure or CPU failure
2,7 memory modules are detected, but a memory failure
3,1 possible peripheral card or system board failure
3,2 possible USB failure
3,3 no memory modules are detected
3,4 possible system board error
3,5 memory modules are detected, but a memory configuration or compatibility error
3,6 possible system board resource and/or hardware failure
3,7 some other failure with messages on screen