In many circuits the ground is often the metal case that

Question

In many circuits the ground is often the metal case that houses the circuit. Occasionally a failure occurs whereby a wire connected to a particular node touches the case causing that node to become connected to ground. Suppose that in Figure node C accidently touches ground. How would that affect the voltages found in given problem?

Problem

In given Figure v₂ = 20 V, v₃ = -20 V, and v₄ = 6 V. Find v₁, v₅, and v₆.