Question Dell T7500 Possibly Motherboard Issue?

Apr 3, 2020
Hi all,
I really need your help as I've been pulling my hair out these past few days trying to get a Dell T7500 to work.
I bought the first unit. No ram, no HDD, no GPu, picked it up for less than a hundred bucks. Ordered a 1TB SSD, x5550 processor an RX 8Gb video card plus a few sticks I pulled out from another R610 I own. Installed Windows 10 and things werre going well except it lasted only a few minutes. Used it for 3 minutes then it froze. Restarted, all well, next 3 minutes or so froze again. Thought it was a processor issue, ordered a X5690 off eBay same thing froze and then after a while it won't come up again. The lights are stuck at solid 3 and 4.
Now the Bios won't even load. It gets stuck at the Dell logo with bar never fully loading until it freezes. I am unable to boot into bios which I was able to before. If for some reason it loads, It gets to the Initializing ../ and it gets stuck doesn't boot past that

Ordered another one few days ago, arrived a few hours ago. Due to the Covid-19, the user couldn't get proper shipping packs to pack the unit probably. Came with a Quadro 3800, ram and hdd. The seller even sent me a screenshot of the pc working before he sent it. Switched it on, it won't display a thing on the screen. I am guessing this could have been to handling during shipping. Found a burn near the processor so I am giving this one a mb problem, maybe? I've checked the forums, reseated the RAM sticks, changed processor and it won't show anything on the screen. No display, nothing. Lights 2,3 and 4 are blinking continously and fan are revving at the highest.

Could both pcs be having motherboard issues ? Any tips you guys could give? This is frustrating.
TIA for your help!