error message ' this build of windows is not genuine'

[CazzaF]

my background screen has gone black and have error message saying my windows build is not genuine..have tried to validate but says not genuine. Have Dell DVD reinstallation OS and product key but have tried entering that and told key is blocked. Bought PC from Sedatech with Windows installed. What to do - am NOT computer literate...help!

 

[USAFRet]

You have a "Dell DVD". Do you have a Dell computer?

If not, that key may indeed be blocked.