I have rated my experience with this seller with only 3 stars due primarily to my experience with the seller and not with a problem with the product.  The computer is pretty much as advertised and works pretty well. (The voice recognition stops working for no apparent reason frequently; it can be restarted.) The only performance discrepancy from the advertisement is that the Windows system page lists the processor speed at 3.4 GHz rather than the 3.8 GHz advertised. I feel that is probably a very minor problem and I would not be able to discern the differences in speed.However, when the computer was delivered, the promised keyboard and mouse were included but the other promised accessories were missing. I contacted the seller but it did not respond until after I contacted the seller through Amazon 10 days later.  The seller then promptly forwarded all of the missing advertised items except for the Operating System Certificate Of Authenticity which I deem to be important.  I again contacted the seller to let them know that Operating System Certificate Of Authenticity was still missing and that I felt it was to be provided as promised. A month has passed but there has been no further response and no Operating System Certificate Of Authenticity.