Screen flickers on and then off after screen replacement?

I replaced a screen on an iPod touch a couple of weeks ago. Everything worked fine until today. When I push the power button the screen flickers on for a split second and then turns black. During that split second I am able to see the lock screen. Also, the home button wont turn the screen on; the screen doesn't even flicker when the home button is pressed. However, I can confirm that the home button does work. After multiple tests I have eliminated a few possible causes for this problem.

1) The problem does not lie in the screen itself.

2) The problem has nothing to do with the power button.

3) It is not software related as the iPod behaves normally in every way that I can possibly test it without being able to unlock it (screen shots, voice over, hard reset, iPod restore.)

I have not been in possession of the iPod in the last two weeks, so I really don't know what it has been through. hopefully not water damage...

Anyways, any help would be appreciated. I would love to know any possible causes and hopefully any possible fixes.