Why am i unable to type in microsoft word?

[Vienna]

After opening microsoft office word, I am able to type but then as soon as
microsoft office home and student pop up appear requesting for a product key.
I have no idea what this means so i cancel it and then start to type and it
refuses stating that "this modification is not allowed because the selection
is locked. I gave had no problems with it up until this. Its getting
frustrating having to retype my documents because they wont open in works
processor

 

[Stefan Blom]

If this is a trial version, it may have expired, which means that it is time
to buy a full version.

If it is a full version, did you activate it?