I also have a VGA TiBook which took a few days off. During the last weeks the machine made some ugly noise through the speakers on startup and did not boot. Reseating the RAM seemed to fix it for a while, but in the end it did not work any more. The RAM itself is known good, as I double checked by swapping RAM modules with another TiBook. Might the RAM socket be the culprit? Or it it just coincidence of manipulating the bord at the RAM socket but fixing a contact problem somewhere else?