I wanted to honestly and sincerely thank everybody. All contributions are helpful. The problem is not so much with my English as with my severe ADHD which basically makes me handicapped. Though some people think that ADHD is an adolescent prank, they are blessed not to know it. EG I'm used to lose my wallet a couple of times a year. I just make an accidental unconscious movement and ... lose track of it forever...
I am touched by such response which basically answers my questions. Here is what happened:
I bought Dell Inspiron with sticker of 1 year subscription for Microsoft Office for this computer.
I need computer with Microsoft Office for internet store project which I have recently started with the help of my friend and other people who are doing internet sales for over 10 years. Since Microsoft Office was not pre-downloaded on the computer, I contacted Dell through online chat and started following their instructions for downloading. However, it didn’t work bc at the last moment appeared small window notifying that downloading is blocked by Microsoft. After several futile attempts, Dell representative finally told that it should be Microsoft’s problem. I reached out to Microsoft, and representative asked for permission to enter through web into computer to examine my software. I gladly gave him permission. After examining my computer, Microsoft representative told that it is the product of 'Dell China' about which they have tons of calls. He apologized that he can not help me much because Microsoft does not have any agreement whatsoever with Dell China, and didn’t authorize this company to put a Microsoft product sticker, and If I want to use Microsoft Office, I need to buy product.
But when I tried to return laptop to Best Buy, they refused arguing that computer contains viruses. 1) I didn't do any operations besides those I mentioned (2) My request to return the item was not an arbitrary decision motivated by wrong color of box, but basically it was at least misrepresenting the product or put it straight contained elements of fraud, and in such case, I believe it is a duty for a seller to return it to manufacturer no matter what.