Second plumbing thread of the day.... My bog standard bathroom sink tap has suddenly stopped working. No cold water comes out. They only symptom is that the tap itself is a bit stiff, and cannot be turned round fully. All the other cold taps in the house seem to be working fine, and there are no obvious leaks. I can just about change a washer on a good day, but otherwise my knowledge of plumbin matters is less than nil. So I would welcome any ideas on what what the problem could be.