Question Newly built pc wont boot

[kenoom]

Hello!

My PC Parts:

MSI B350 PC MATE
Ryzen 7 1700
8GB G.Skill Aegis DDR4-3000 DIMM CL16 Single
600 Watt Be Quiet Power Supply Non Modular
GTX 770

I have been building a PC for my little sister but unfortunately I've ran into a problem.
The problem is that I can't get into BIOS and the BOOT_LED is lighting up red.
GPU Fan and CPU Fan are spinning, the monitor is recognizing an input but isn't showing anything.
I have tried following things:

1. Reseating the Ram Slot
2. Reseating the GPU
3. Only booting up with USB drive with Windows 10 ISO
4. Booting up with my own SSD, where Win 10 is already installed (got into a boot loop but then I cleared CMOS with JMOS. Then I ran into the same problem that BOOT_LED is lighting up.)

I'm certain that the CPU is installed correctly and the GPU aswell.
Of course I am plugged into the Graphics Card and not into on Board graphics.

Any tips would be appreciated.

 

[logainofhades]

Assuming you are using a single stick of ram? If so, try different slots.

 

[punkncat]

Manual states that the boot light is indicative of the boot device not being recognized.
Perhaps check your power connection, use a different SATA cable?

 

[kenoom]

Assuming you are using a single stick of ram? If so, try different slots.

I tried all Ram Slots and didnt work unfortunately.

 

[kenoom]

Manual states that the boot light is indicative of the boot device not being recognized.
Perhaps check your power connection, use a different SATA cable?

I have tried different SATA Cable and different USB Slot, didn't work.