How can I measure accurate resistor value in PCB with HP34970A in labview 7.1?

[Labview Resistance Measurement]

In labview, with the resistor not soldering on PCB, I got the accurate value of resistor by using HP34970A Measurement in labview(GPIB). However, with the resistor that is soldered on PCB(PCB no input source), I couldn't get the stable value of resistor, resistance is variant. Any one can help me to solve the problem?

Thanks!

Vien

[AndrewAlford]

You will never be able to read the acutual resistor value while it is in circuit. Even when the circuit is not powered the other components in the circuit will affect the reading