This is something that really annoys me. I offer the following advice. When you buy goods you enter into a contract with the seller of those goods. Under the Sale of Goods Act 1979 goods must be 'as described', ?of satisfactory quality', and 'fit for purpose'. This means both their everyday purpose, and also any specific purpose that you agreed with the seller (for example, if you specifically asked for a printer that would be compatible with your computer).
Goods sold must also match any sample you were shown in-store, or any description in a brochure.
In most cases, your rights are against the retailer ie the company that you enterted into a contract with, not the manufacturer, and so you must take any claim against the retailer as this is the party you entered into a contract with. However, if you have bought something on hire purchase, it is the HP company that is responsible.
If you think you have a claim under the Sale of Goods Act for one of these reason above, you have several possible remedies, depending on the circumstances and on what you want done.
If you want to get your money back. If you buy a product that turns out to be faulty you can choose to 'reject' it: give it back and get your money back. However, the law gives you only a 'reasonable' time to do this ? what is reasonable depends on the product and how obvious the fault is. However, even with something like a car, you usually have no more than three to four weeks from when you receive it to reject it.
If you want to get a faulty item replaced or repaired
You have the right to get a faulty item replaced or repaired, if you're happy with this (or if it's too late to reject it). You can ask the retailer to do either, but they can normally choose to do whatever would be cheapest.
Under the Sale of Goods Act, the retailer must either repair or replace the goods 'within a reasonable time but without causing significant inconvenience'. If the seller doesn't do this, you are entitled to claim either reduction on the purchase price, or a refund, minus an amount for the usage you've had of the goods (called 'recision').
If the retailer refuses to repair the goods, and they won't replace them either, you may have the right to arrange for someone else to repair it, and then claim compensation from the retailer for the cost of doing this.
You have six years to get a claim in to court for faulty goods in England, Wales and Northern Ireland; in Scotland you have five years.
What you need to do to prove your claim
If your claim under the Sale of Goods Act ends up in court, you may have to prove that the fault was present when you bought the item and not, for example, something that was the result of normal wear and tear.
If your claim is about a problem that arises within six months of buying the product, it's up to the retailer to prove that the goods were of satisfactory quality, fit for purpose, or 'as described' when it sold them e.g. by showing that the problem was caused by an external factor such as accidental damage. Beyond six months, it's up to you to prove that the problem was there when you received the goods even if it has taken until now to come to light.
So you may need to prove that the fault was not down to ordinary wear and tear or damage you caused, and that the product (or a component) should have lasted longer than it did. To do this you may need an expert's report, for example from an engineer or mechanic.