Vat liability

Dear Fellow Members

Please help me out in knowing that

if a company is not regd. under VAT, but in the course of the business it comes comes across cetain activities which covers VAT liability eg. Sale of Second hand /used motor car to any entity etc

Then is the company liable under VAT compliance ?

Please advice with some proof in respect of both the liabiity of company as how to ascertain /pay such Tax

With Regards

Mannu Jagnani