Screen unresponsive after screen/digitizer replacement

The screen cracked, and although iPod was still working fine I decided to replace it because it didn’t look so pretty anymore, so I bought a replacement screen/digitizer. I carefully replaced it, but then found out that a small portion of the screen isn't responding. It is an area of about few millimetres going all the way from left to right in the lower part of the screen. It’s where, for example, virtual keyboard’s second last row sits. Hence, if I wanted to type something, I couldn’t use any of the Z, X, C, V, etc. I tried to do restore, but it didn’t help. Then I tried putting in another (working) screen/digitizer from my second iPod, but I’m still having the same issue. Please help.