iPod wont turn on after screen repair

hello, i just replaced a screen on a ipod 4g, after connecting it all together ipod functioned great no problems. then when screwed in all the screw in there place it began to flash constantly with the apple logo,i tried the reseting technic hold POWER AND HOME both down.. it stopped the blinking. but now it doesnt do nothing. computer doesnt even recognize it when charging on wall doesn't show nothing.. ive checked every thing over and over and no repond someone help.. everything in the ipod is tacked ..