You aren't looking to find the temp of a fan, but the temps of the hardware the fan(s) are cooling. We need to find which components are overheating to determine where to look for the problem, and likely what is causing the problem.
When you get to the BIOS, look for something like Health Status, Hardware Monitor, System Health, Sensor, or something similar. It should say things like MB (motherboard) Temperature, CPU Temperature, maybe HD Temp, etc. If your CPU Temp is running high, if you don't get it figured out very soon, it could cause irreparable damage to the CPU, MB, and more. The other choice if you don't want to go through the BIOS, I recommend use a different program to compare to SpeedFan's readings. Everest and Core Temp are two other good programs.