Latitude E6530 Boot Issues. Only boots doing specific sequences

OK. I am quite tech savvy and have gone through a very vast majority of scenarios to try and diagnose the issue with the PC.

First, I got this laptop second hand. I know enough about it to know I shouldnt have purchased it.

Problem: Original problem: Laptop wouldnt reboot or shut down normally at all on Windows 7 Pro 64.

New Problem: I decided to wipe it and load a copy of Windows 10. Although it powers down normally. It now powers on, blinks the HDD light, 30-seconds on the dot, it powers down. No video, no backlight, no splash screen. It also does a bizzare reboot procedure.

It will not boot with AC Power attached. Only battery.

Ive now narrowed down a few boot up sequences that make it work (85%+ on the time)

- Remove Both Memory DIMMS. Insert 1 DIMM in Slot 2 (top slot) and boot. Shut down and install 2nd DIMM.

-Remove Coin Battery and reset CMOS

-Holding down the shift key a few seconds while booting or shortly after booting seems to allow it to boot most of the time.

Restart Problem: Unit goes to shut down. Power light stays on then goes off. HDD< Batt and WiFi light up. HDD flashes 1 time for 1-second interval. If I push the power button, it turns on.


What Ive done:

-Replaced RAM

-Replace Coin Battery

-Reseated CPU

-Checked all connections to MB

-Downgraded from A19 to A18 BIOS

-Upgraded back to A19 BIOS

-Went through every BIOS setting

-Went through every Windows 10 power setting (hybrid power disabled)

Prior to finding the above sequences to get it to boot, it would go over 30+ attempts with no boot up/no video.

Im 95% sure its the MB. But Id like to get other peoples input