HTPC Crashing / No Signal

[Rensin]

Hi,

I built my HTPC about 6/7 years ago and have had 0 problems until a week ago.

I can be watching a movie and the HTPC will randomly crash (screen freezes) ... nothing will work so have to hard reset.
While booting backup there will be no signal on my tv, I have to leave the HTPC for a few hours before it will boot properly and will work ok for a bit and do the same again.
Also while booting the pc I don't always get a signal so again have to leave it a bit to get a picture.

My HTPC BSOD last night and got an error "memory management" upon restarting I got several different error codes (can't remember what they were)

I have tried the following:
New GFX Card (6450)
Tested onboard graphics
Tested each stick of RAM for 12 hours each with memtest 86 with 0 errors.
Tested another stick of RAM
CrystalDiskInfo shows SSD to be Good Health with 0 errors
Cleared CMOS
Clean install of windows 7 (was windows 10 but the drivers are not officially supported)
PC is connected via HDMI.
Dismantled the whole HTPC, cleaned and put back together.

I'm out of ideas so would appreciate some help please

Spec:
asus p8h77-m
i3 3220 (stock)
8GB DDR3 Corsair
MSI 6450 (Passive Cooled)
Corsair 540w PSU
Samsung 840 Pro 128GB

 

[Rensin]

I can order a new psu to test.

Also I have just reinstalled windows 7 to another drive using onboard gfx and the screen is dark.

Windows won't recognise the ethernet port and won't let me install the driver.

 

[Rensin]

I'm on the latest BIOS mate, the mobo is old now so no new updates since 2013 I think it was.

My initial thought was the RAM but have tested both sticks plus another stick from my homeserver and problem is still there.

I'll grab a replacement PSU and test this.

 

[Rensin]

ok, tested with a new PSU and still have the same problem.

I think I may of found the problem, if I only install 1 stick of RAM it will work ok, if I install 2 sticks it won't boot (have tested different RAM & memory slots)

When 2 sticks of RAM are installed the DRAM_LED is constantly on (Red) ... could this be a faulty mobo?