Dm800 boots sometimes, very moody

Hi people, ok I'm trying to fix a friends dm800hd clone. The problem is , it has become very moody when it boots up, I would say it freezes whilst booting 1 in every 3 times. Sometimes on certain images it wont get past the booting process at all [perfectly good images which I installed on other dm800 clones].
I have tried at least 5 different versions of open pli [fresh, aswell as backups. even the doods backup floating about online] Some initially work then refuse to boot/stuck on boot cycle after restart. Others just refuse to get past the booting bar process.
Is the flash memory damaged in anyway, As when I received the box from my friend, the flash was running at 99%. The image was blackhole v1.66 . The autobouquets e2 refused to work for lack of space.

So to some up, I can flash images to the box, but they get stuck on boot occasionally/randomly
The box in question is a clone DM800 HD SSL84B Production date 08/2012
Any help will be appreciated
Thank You

Quote from bh0y

try other psu mate

they notorious for struggling on power up etc

Yep, I tried another psu, still acting moody
Is it possible that the flash has gone faulty?

Right new development,
Now when the box gets stuck on restart or restart gui, If I leave it stuck, say for 4-5 mins it automatically reboots fully and eventually boots up.
what is going on? any ideas

anniman and rami, thanks for your input,
I flashed a fresh openpli, took out the tuner. It seemed to boot up most of time without issue. Also after I reseated the tuner, it seemed to boot up most the time.
Now it hangs maybe 1 in 5 boots[ and only at the very start, the boot.jpg bit. Before it was during the bootup line across the front screen]
I think this is as good as it will get on this particular dm800 so Ive given back to the friend.
Thanks