If a company ceases to operate, they are obliged to return their employees to the country where they were recruited from, and provide them with economy class ticket.
If you are working with them for 1 year or more, they are also obliged to pay your end of service gratuity. Computation shall be based on a minimum of three-week wage per year, and any fraction of days work thereafter shall be paid in proportion to that amount.

Sadly, the release of NOC is purely upon the discretion of the employer.

Hope this helps. (Source: http://www.qatarembassy.net/Qatar_Labour_Law.asp)