Well, one temperature candidate is intentionally lying. The other is just wrong from sheer ignorance. Which is worse? B) (Sorry, couldn't resist!)
Which one of those readings was from bios? You should be able to get a good baseline from there to tell which software is correct. If Sandra's matching it, I'd think Via HW mon was reading incorrect before. You can manually calibrate MBM to read correctly if you know the error delta.
Pentium IV 2.4C Northwood- M0 stepping @ 3.2GHz HT
Air Cooled w/ SP-94 heatpipe & 92mm Vantex Tornado at 45C
4x256=1gb dual-channel 2-3-3-6 OCZ PC800DRAM @ 890MHz 3-4-4-8
MSI Neo2-PLS w/I865PE & SATA @ 4x267=1068MHz
BFG GeForceFX 5900@485/967MHz = 6284 3DMark2003s; dual-head 21" CRT & 19" LCD