strange - took phone apart, now screen is scrambled topic

hi all, hope someone can maybe help me.

i disassembled my nexus 5 to change the frame. i followed the excellent tutorials on youtube and followed to the letter, no issues or broken items or difficulty. the disassemble was very careful.

when i power on the device afterwards, the screen is totally scrambled and unusable. i've taken it apart again about 7 times, checked all connections, etc. but no solution.

has anyone heard of this? i'm dying here grrr. thanks.