now THATS odd!!
firstly look at your MB book and set the multiplier setting manually instead of it being set to auto detect(defualt).
if thats done look at the FSB make sure it hasnt changed as sometimes little things like that can happen simply enter BIOS and set it back or again do it by a jumper setting on your MB.
if thats all ok find the latest BIOS flash for your MB as you may have a dodgy BIOS.
and finally if thats done try a format of your drive as there is a file that windows uses to ID your processor speed make etc. and it may of become corrupted.
if all that dont work email me at [email protected] dont use the PCA email service as that email addy is long since dead