Dell optiplex 780 SFF, motherboard stuck to case?

[XistenZ]

So I got a hold of a Dell optiplex 780 Small Form Factor, which doesn't run very well (powers on, then nothing). I'm guessing the PSU's gone bad so I wanted to try it out with one I know works, but since it's Dell nothing will fit, so I'll have to do something original BUT to do that I need to get the motherboard out of the case.
I've been looking for videos on how to do it for half a day now, and the only manual I found was for a completely different computer than what it said. I removed all visible screws and detached everything going to the motherboard. I've removed anything that can be removed in the hopes of some little screw hiding, but nope, nothing. It seems like Cthulhu himself is sucking this thing back from under the board.

Anyone that knows what I'm going through, or got better luck in finding tutorials on this? (guessing there's no tutorial because it simply can't be done). Would hate to destroy the case just to try my fix out because I'd like to keep it, and buying a new PSU that might not even make it work sounds unnecessary.

 

[Ubrales]

It is definitely not stuck to the case with any kind of adhesive. After removing all mounting screws, look for tabs that the motherboard may be hooked under (this may not be the case). Then using a flat screwdriver, apply side pressure to the motherboard edges to break the bond between the motherboard and the mounting bumps. This bond is due to the parts being held together for a long period of time.

(I had similar issues when I tried to separate the heatsink from the CPU on a Dell Optiplex 755).

 

[XistenZ]

There's no tabs and all screws are out. I can lift one side of the board off quite alot (so much that if it were only bond due to time it would've snapped off already). The other side is still stuck, there's openings in the case so I can look under the motherboard to see where it's attached and there's nothing left keeping it there. It's pure magic...

 

[Ubrales]

There's no tabs and all screws are out. I can lift one side of the board off quite alot (so much that if it were only bond due to time it would've snapped off already). The other side is still stuck, there's openings in the case so I can look under the motherboard to see where it's attached and there's nothing left keeping it there. It's pure magic...

From this it looks like there is one fastener that is still in place. Maybe does not follow the pattern of the rest.

 

[XistenZ]

Oh darnit I feel retarded... There were, of course/obviously one screw left, but it wasn't a traditional screw! It was kinda camoflaged as a bit of electronics really... It was a "cylinder" distance used to fasten the PSU (the PSU was of course removed, but the cylinder was hard to spot).
So yeah, for future finders! The solution to this magic trick is to remove the distance for the PSU.