There are a lot of temps listed in Speedfan that aren't right. The temps that are really high or really low are usually ones that aren't being reported correctly - because it's a sensor that isn't connected (or even there). No worries. I would check in your BIOS what your CPU temp is, and there is usually a temp that is similar in Speedfan. Your HDD temps you can usually find easily, just press "Configure", and you can set up which ones are displayed.
EDIT: And you can sometimes use EVEREST to compare temps, and label the ones in Speedfan accordingly.
EDIT: And you can sometimes use EVEREST to compare temps, and label the ones in Speedfan accordingly.