I would trust the BIOS more so than a third-party win32 program that does most of its work based on registry entries.
does windows see your computer as a 1.2ghertz when you right-click on mycomputer and hit properties? If not then you might need to update some stuff. the VIA 4-in-1 drivers first (4.33 are the newest if im not mistaken), and maybe windows XP to SP1 if you havent done that already...
In sum I would not worry what wcpuid has to say about your processor. Now if your (updated) BIOS says something else then you in trouble... IF so then i would take a hard look at the processor itself, speciffically whats written on it and the serial number.