I received shipping notice late yesterday that he was on his way home, and sure enough, he's now back with me where he belongs. ^_^ The work order is the usual terse (semi)descriptive info, and as expected, the motherboard was replaced as, apparently, was the thermal module. I guess the fan was no longer ramping the way it was supposed to. However, the surprising part was what it was replaced with. The new motherboard is the upgraded board in the current model such that I now have 3GB RAM (vs my user upgraded 2.5GB on the old board) and the graphics chip has been upgraded from the 128MB nVidia 8400G to the 256MB 9300G.
He seems a bit noisier than he used to be, although that might also be me and my almost silent days with Haku. (Haku's fan is extremely quiet.)
The plus to the repair is that a disconcerting flicker when opening/closing the lid is no longer there either. ^_^ The negatives...? Um... his cover's a little dirtier than when he went out, so I'll have to remember to clean his lid. All in all, I'm really happy and impressed. Shipping was completely paid for, and the turnaround time was very short (Tues shipped out~returned Fri) compared to my previous Toshiba repair (3 wks in town). Unfortunately, I've heard that Asus's repair services vary heavily according to where you live. North America is supposed to be excellent while UK sounds like it might be worse than excrement.
No word yet on what's happening with male parental's system. I'll have to corner him sometime this weekend. >.>