Because the inverter's only function is to generate a high voltage for the CCFL backlight, it cannot produce the line artifact that the OP described. So that's one thing you don't need to check.

What you are seeing is also not the result of "interference."

What you do want to check for is a loose or damaged cable, or a poorly seated daughter card, as bluekatt mentioned. If the symptoms first appeared after you pulled the unit apart, then the most likely explanation is that something didn't get reassembled quite right, or the delicate flex cable that connects the LCD to the logic board got damaged. Do a careful visual inspection, and you'll likely spot the problem. The CPU daughter card is frequently a source of trouble because it needs to be firmly seated; a little bumping during disassembly, and things get disconnected. Symptoms can range all over the place, including the "no boot" condition with funny display patterns.