I have on my Dell computer MS Office 2010. I am using Windows 7 64 bit.
A pop up says I need a Product Key. After surfing the Internet for
buying a MS Office Package (Office 2010, 2016)... I am at a loss on
what Internet website I can trust. Can you recommend several websites,
retail stores etc. And perhaps I can just purchase a Product Key.

A prompt reply will be helpful. Thanks for your help.

Sy