overheating no display

[dummy]

I have been having trouble with my computer overheating that came out of the blue. So I tried cleaning out the dust with no improvement. So eventually i fiddled with my water cooling system, upon putting it back together my computer no longer displays. What may have gone wrong?

[fenyal]

is everything in the system seated correctly? make sure, some times things can get knocked out of place by just a little nudge.

do you hear any post beeps?
did you break away any cpu/gpu cooling blocks? if so did you reapply thermal paste?