Bumped a doohickey out of its thingamajig
When my charger was plugged into my iBook, the lightning bolt icon would flash on and off and on and off, and the iBook wouldn't charge. If I pushed the plug in real hard and held it with all my meager strengh, it would charge fine, but this was time consuming to put it mildly.
The repair went fine, though the first time I put the iBook back together, I got the dread question mark flasher. I reopened the thing and upon inspection found that I had apparently dislodged one of those ribbon-plugs. I plugged it back in, put the whole shebang back together, and now it works like new.
I know almost zero about computer innards but the ifixit instructions are so good that the process went smoothly, except for the above. My advice is like that of others: go slowly and if the iBook doesn't work when reassembled, open it up again and see if you have unplugged something by mistake.