Under consumer law, the first twelve months is the responsibility of the supplier to deal with any repairs or warranty work.The manufacturer,in the case of monitor's,usually provides a further two years of warranty cover. Having said that, it is usually quicker to deal with the manufacturers service facility, especially if they have a 'swop-out' arrangement.
Check the warranty card and see what it states. Some cards can be registered over the phone or internet. Other cards may require posting, and other cards need to be kept, and then provided when a claim is made.You may also find that it is best if you staple your purchase receipt to the card, as this will be taken as proof of purchase. If you have to send the card away, keeps copies of what you have sent.