M4A88T-V EVO -- Can assume dead?

[Rodrigodrt]

So just out of the blue my sister's PC didn't wanted to boot anymore, it fires up but no beeps, and a curious thing that happens is that it can't be turned off by keeping the power button pressed, just by turning off the power supply or pulling the cord directly.

So far what I've done:

Cleared CMOS and changed the battery
Unplugged every peripherals and unessentials
Swapped and cleaned RAM memory
Removed the processor and installed it back
Kicked the case kinda hard

No avail.

What I've noticed:
It won't boot but the monitor still reacts, and then goes into power saving mode
without the RAM memory it does beep three times or so, with it, no beeps
The processor doesn't heat, I removed, inserted it back and touched to see if it heats up but no avail
For a moment I completely removed the CMOS jumper and forgot to put it back, and powered it up this way, it acted just the same as if the jumper was in place, if I recall correctly, other PC's that I've done this wouldn't even turn on
Tried to boot on on-board video rathen than with graphics card

Can i assume it's the mobo? it uses an old Phenom II x4 965 BE processor, a 750W CS series corsair PSU, 2x8 Kingston RAM, GTX 750 Ti

 

[thx1138v2]

It could be the motherboard but I've seen them act weird if the voltages are out of spec or in spec but then go out of spec under load. If you have another PSU try that first.