My iPod Touch 4G screen cracked while playing, and so we had to replace it. I bought a screen replacement, and decided to do the work on my on. So I fixed the new screen, as directed on a guide on iFix it. From then on, it would work fine, except once in a while a series of white lines would appear, completely covering the screen. You could see only about 20-30% of what was going on on the iPod, the rest was just white. This could be fixed by just tapping, or turning or shifting the screen a little. One fine day, the screen went permanently white, and no matter how much I wiggled or moved the display cable, it would not get back to normal. After a number of days, I decided to buy a new screen, and replace it. I re-did the procedure as before, and turned it on. The first time, the screen appeared VERY dim, barely visible, even though the brightness setting was at maximum. I thought this was a problem with the alignment of the display cable, and so without switching off the iPod I disconnected and reconnected the display cable. The iPod has not turned on since, and I know this because I have tried a hard reset, but it does not show up in iTunes. Also, I tried connecting it to a charger, but in vain. Could this be a Power button failure? Or Home button? Or something with the logic board? Please help, thank-you.