Had a bit or a roller-coaster ride
 
I tried to remove SP2 (arstechnica thread mentioned that) before transferring the motherboard - and it came up!
Specifically, I did the following preparations on the old computer:
Replace Via IDE driver with Standard.
Replace Via PCI-to-AGP driver with Standard.
Remove Via AGP filter (the only non-plug-and-play device that had Intel or Via in the name).
Disable Kaspersky Internet Suite 7.0.
Remove SP2.
Moved the HDD to the new computer.
Came up with SP1!!!!
I then installed the new drivers from the CD, all's well except there is still an "unknown" device supposedly connected to the PCI-to-ISA bridge. No further information that I could find.
Now the downhill part: After it was all running at SP1 level (Kasperky still disabled), I did an upgrade (run Setup from the CD) from the SP2 slip-streamed CD (the one that had done a good fresh install above) - blue screen again.
The specific data on the BSOD is:
Check 0x0000007E (0xC0000005, 0xBAA78750, 0XBAACCB42C, BAACCB128)
The arstechnica thread points to 
KB888372, which acknowledges the possibility but doesn't give a solution. The arstechnica author says 
	
	
		
		
			I was able to get service pack 2 working ONLY after I deleted the IntelPPM and IntelIDE keys from the registry under current control set.
		
		
	 
I hope I can do that in safe mode and not need to redo the whole sequence.