Testing PC power cable
Use a multimeter to test for continuity from the plug end to the line socket end.
Test the cable on another appliance. Flex the lead and see if the appliance switches off. Pay particular attention to where the lead enters the plug or line socket as this is a common point of failure due to flexing.
Apply a known current of several amps through each wire of the cable in turn and measure the voltage drop along the conductor carrying the current. Calculate the resistance from \$ R = \frac V I \$. Compare this with the value calculated on one of the many web voltage drop calculators. Compare the readings from the L, N and E conductors. Is one higher than the other?