PC won't POST after new setup

[DenShazo]

Recently my previous PC, a Dell XPS 8900 with an Intel core i7 6700 processor, started giving me errors stating that the motherboard fan was not working properly. I opened it up and saw that despite the error  message, all the fans were spinning. Unfortunately whoever prebuilt the machine screwed the heatsink in to the point that removing the processor was impossible.

 

So today I bought a new case, used motherboard (Gigabyte H370 Aurus 3 wifi), used processor (Intel core i7 9700k), and new power supply (Thermaltake SMART 600W). A friend and I then transferred over the RAM (Corsair Vengeance LPX), GPU (Gigabyte GTX 960), and the hard drive from the old XPS into the new custom build. We noted that the video input was only detected when the hdmi cable was connected to the GPU. When we booted the PC it would freeze right before it accessed the hard drive. We went into the BIOS and it detects the hard drive, but when we try to boot from it it says to choose a proper boot device and try again. The hard drive was fine before the xps 8900 failed.

 

Already tried reseating the CMOS battery and running the machine without the GPU as per advice from other friends who are experienced with building and troubleshooting computers. The current consensus is that there's a clash going on between the hard drive, which has windows 10 installed on it, and the motherboard, and that reinstalling windows should fix everything. 

 

Is there any other thing I can try before resorting to a wipe?

[GDRRiley]

you need a windows install on a flash drive or disk to fix the MBR and apply it to the new computer.

 

I had to do it when moving my SSD from my old laptop to my new laptop.

Edited December 7, 2019 by GDRRiley

[DenShazo]

1 minute ago, GDRRiley said:

you need a windows install on a flash drive or disk to fix the MBR and apply it to the new computer.

I see. I really hoped it wouldn't have to come down to that, but I do appreciate your input. Thank you.

[GDRRiley]

Just now, DenShazo said:

I see. I really hoped it wouldn't have to come down to that, but I do appreciate your input. Thank you.

you aren't erasing anything.

[DenShazo]

So I don't have to format the HDD to run windows?