best tool for this for windows 7 is OEMdump, its safe and fast , it give you the product key , plus a backup of your cert ( activation certificate) and a copy of the slic (bin) from your bios. instantly.
I downloaded OEM dump and it retrieved the product key which does not resemble the few odd characters on the windows label. Looks like Im going to have to ring Microsoft. Unless theres something else to try????
OEM dump never fails ,it has given you the correct OEM KEY for your PC, the key on the label is a COA key (certificate of authenticity) , this will not work if you had to reinstall for any reason. the key and cert you got from OEMdump are correct 100%, why are you bothered anyway ,if your machine is indeed genuine ,microsoft will help if you have any problems .but be aware of the terms and conditions of using OEM software.
Very simple to find it and all the other licences for software on your pc. Simply download Belarc Advisor and run it. It is free and a very useful thing to find out every detail of your PC's hardware and software
I have used it for many uyears and you can download it from here