XP hangs on boot up on P4C800E-Deluxe

Six year old home built PC:
Asus P4C800E-Deluxe MB
4ea HD's; one pair in Intel Raid 0 array, other pair on Promise controller but not Raid.
Antec Sonata Case (used to be very quiet)

Replaced dying power supply with one which does not have special connections for case cooling fan. Connected fan directly to molex connector, everything fine except for high fan noise. System booted up and operated as expected.

Installed 'Twister' fan spd cntrlr. No fan at first but did get 'Overclocking error.' Reconfigured fan connections (now correct) but system hangs while booting at 'Windows is starting ...' screen (light blue background, small logo).

Using XP install disk - Recovery Console - system hangs at 'Examining 953868 mb on disk ...' (Size corresponds to the effective size of the Intel Raid array disks.)

Fortunately all data files were backed up to an external hard drive while system was working (although with very loud fan.)

During bios boot the system indicates that both Raid systems are 'normal.'

I suppose it's possible that: (1) an improperly connected fan might have done something to the Intel controller on the MB (wrong voltage going somewhere); or (2) coincidentally one of the Intel Raid disks failed at the same time. Note that the system boot appears normal until the hang point so some data is being supplied by the disks. All connectors seem to be secure.

Any help, thoughts, suggestions will be greatly appreciated.