If you receive the following during boot:
STOP 0x0000001e (0xc0000005, 0x801a8a83, 0x00000000, 0x005c0069)
KMODE_EXCEPTION_NOT_HANDLED Address 801a8a83 has base at 80100000 - ntoskrnl.exe
you may have a corrupt SOFTWARE hive.
If your ERD won't repair it, it probably is registry corruption.
The safest method of recovery is to restore the SOFTWARE hive from a backup.
If you don't have one, you could try tip 0505, replacing only the software hive.
NOTE: You will loose registry entry made since the last RDISK.EXE execution.