Hello!
I'm in the same position. I dissasembled mine to try and fix the display cable (their common problem), so I fiddled around with the backpanel and reasembled it back, pressed the On button and nothing happened. I switched the cooler/fan but it was in vane...
When I press On the button lights up, the HDD led flickers once and the HDD starts, that's all! No image, no fan starting, no light, nothing!
What can be the problem?