I have had some trouble with installing a 512 Mbyte SODIMM in an iBook G4 (12", 800 MHz) recently. I tried two different parts (at least Crucial says they were different) and each failed similarly, so I was wondering if anyone had any ideas, thoughts, or suggestions. Here's the story: after insertion of each card (under the AirPort Extreme card, after unscrewing the four *tiny* (soft metal) screws) of the shield), I reinstalled the shield, reinstalled the AirPort card (yes, with enough pressure), reflipped the crummy wire bail, and after reinstalling the battery, the iBook failed to boot. The LCD didn't come on (dark), the chord didn't play, and after a few momets, the fan came on (loudly, I might add). The fan continued to turn until I popped the battery back out. I tried this several times with each part so I am confident everything (RAM and the AirPort card) were well-seated (yes, I've installed lots of SODIMMs, but never before -- and perhaps only once more -- in a Mac). Once, I left the AirPort card out and guess what -- the thing booted and reported 640 Mbytes of RAM (then, elated, I reassembled everything and nothing worked, alas). BTW, both times, I reassembled the iBook with the original 128 Mbyte SODIMM with joy. The Crucial tech support guy(s) just said, "duh!" Perhaps notably, the 512 Mbyte part is a double-sided DIMM and the original is single-sided. A few mentions of this failure (fan only) have been made on the Apple discussion boards (due to Crucial RAM, AirPort insertion problems), but none mentioned any resolution involving Crucial RAM. I did get my money back from Crucial, BTW. Any ideas and/or suggestions (cheapo RAM, transintl.com RAM, OWC RAM)? Is there a physical-fit issue with the double-sided part? Apple's BTO RAM seems like a good option, in retrospect. I'm open to suggestions. Thanks.