What Sensor's should I check

This depends on your motherboard, below are a few examples:

Asus TX:

• Check the WinBond Sensor 1/LM78 sensor for your Motherboard temperature
• Check the LM75 sensor for your CPU temperature
• Uncheck the WinBond sensor 2
• Uncheck the WinBond sensor 3

P2 Board with only a LM78 (Asus P2L97 series for example)

• Check the WinBond Sensor 1/LM78 sensor for your Motherboard temperature
• Uncheck the LM75 sensor
• Uncheck the WinBond sensor 2
• Uncheck the WinBond sensor 3

P2 Board with a WinBond W83871D (Asus P2B series for example)

• Check the WinBond Sensor 1/LM78 sensor for your Motherboard temperature
• Uncheck the LM75 sensor
• Check the WinBond sensor 2 (IF you have an extra sensor attached)
• Check the WinBond sensor 3 (IF you have an extra sensor attached)