Hey fella,
There's a chance you may have damaged the battery connector. Try plugging the
iPhone into a computer, if it's recognised after a few minutes you could have been sold a dodgy screen. Or it could just be that the process has completely drained the battery and could need charging for a bit, try plugging it in for around 10 minutes, if you don't get any response unplug it to prevent any further damage. Or take the battery out and check the ribbon, there's every possibility that you could have torn it, even the slightest tear could render the battery useless. As well as this, make sure that all of the connections are properly seated at their points.
Hope this helps.
Hi. Does it turn on if you put the charger in?
by alex
No it does not turn on
by sergii1414
have you tried the old screen back in the iPhone? it could be a fault with the screen or as some of us are finding the screen is ok, phone is ok, they just don't like each other..
by pollytintop
I put the old screen on aswell but it still didn't turn on
by sergii1414