can't type text, but can edit and save

[Guest]

this is weird...i can't type any text in office xp
software (word, excel, pwrpoint, access, outlook), but i
can open files....highlight text with the mouse, and
press "delete" and save these files. I can also start
new files. I never had to activate this product as it is
a student version, and it worked fine until a week ago.

any ideas? when i click on "activate product" it says
this product has been activated.

please help....