MP 1,1-5,1 Mac Pro 3,1 - Red light - no Bootup- No input

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I have a Mac Pro 3,1 from the range of 2009-2012, Xeon e5 542 it originally came with a GTX 680 but i replaced it with a GT 740 and worked just fine, i also replaced the hard drive with the OS because it was faulty, the computer seems to have no bios whatsoever, i had an hdd with windows 10 installed, i thought it would be cool to have a mac with windows, when i plugged it in the computer worked just fine, it could but up windows normally, after some months of use the hard drive was beginning to have issues, the drive was faulty so i had to remove it, after that a couple of months have passed and i bought a SSD Sata, i installed windows using my test bench and plugged the ssd in the Mac, but when i turn on the computer a red light appears on one of the ram slots below, all of the fans are running and the ssd is working fine, but the screen says "no input device detected" and then proceeds to turn pitch black, the computer will stay like that until it is turned off.

Any ideas??

The image attached it's not mine, it's similar to what happens to me.

 

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Update: The red light was solved by removing DIMM 4 on the ram board, the graphics is discarded because it worked jut fine on my test bench, it turns on normally but doesn't seem to boot whatsoever.