The two year warranty begins as soon as you buy it regardless of whether you install it or it just sits in the box. If there is a problem with the motherboard within the warranty period, you go to the manufacturer's website and request an RMA. You need their authorization before returning anything. They will repair or replace it at their option, usually. Depending on the retailer or online e-tailer you get it from, if you discover a defect within a certain period, like 30, 60 or some number of days, you can RMA it to that seller for replacement. Again, you have to get an authorization. It varies depending on what it is and where you got it from. After that period, you then have to deal with the manufacturer.
Don't take this the wrong way, but could you please make an effort to punctuate your posts instead of making it one long sentence? It's difficult to follow what you are trying to say.