dell xps solid amber power light

hello everybody, im new to this community, but i have a real problem which i need help with!! i have a dell xps 600 here, the power light is solid amber, i have replaced the motherboard, graphics card, and also the power supply! still amber power light!! also has 2 new ram sticks, the mobo is a reman from dell, the ram is from 3b tech, and the power supply and graphics card is from ebay, but both members had great ratings, i could really use help on this one, as its not my first go around with computers, i have actually considered opening my own shop on my past time, that is till this one came along! lol, it has 4 trouble identifying lights which one of them is lit, #4, and it says (If the power light is steady amber ??? The computer is receiving
electrical power, but an internal power problem might exist.
Ensure that the microprocessor power cable is securely connected to the
system board.) i cannot figure this out to save my own life, so help is greatly appreciated! the dell service tag number  thanks in advance!

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