Assuming that's a genuine question, then the answer is you don't of course.
The original poster said he had "vastly" different temps show in two apps. Two my mind "vastly" indicates more than 2 or 3C, an amount Sandra adds as compensation on some boards.
So one app (or both) are wrong. With the temp stable in Windows, he can note the two different values then quickly reboot, enter BIOS and check the temp there. (CPU temp shouldn't have change much in the time it takes to do that.) The app closer to the BIOS reading is likely correct.
MBM is shareware... works with most all motherboards that have temp monitoring and since your BIOS shows your temps, you have temp monitoring. Get it at Tweakfiles. I got a date with a hot freshman chick, so I gotta go. Out