Not at all. If you buy a computer with a COA on that case then it is an assurance that the operating system is legal to transfer from one individual to another...If there is no COA (for the operating system installed on the computer) involved with the sale then you should not buy it...as it is a strong possibility that it is pirated software.

There are a lot of ebay sellers quoting that the computer has an attached COA and thus making the pretense of a legal sale that when delivered the COA is not the same type as the operating system that is installed. That is pirated software and the sale is illegal....Tha COA attached must match the same type as the operating sytem that is installed for the sale to be legal.

Once it is determined that the COA is legit and matches the installed operating system then that coa can continue to be used for reinstallion of the operating system to the computer the COA is attached to....it cannot be transfered to another computer legally!