Well, when a company is established for a partiular purpose eg. to carry out project, the company has to be wound up after the completion of the project. Most of the time, companies making losses for a long time are wound up. By mutual agreement of share holders also a company can be wound up. A court can order to wind up a company because of violation of law of the country. Whatever it is, winding up a company is more difficult than forming a company.