|"I have used more than 25 times"|
The 25-uses limit means it's only a trial version. You cannot extend it. You have to buy a full retail version of MS Office, or contact Microsoft to see if you can purchase a new licence and Product Key for the version you already have.
But I'm almost certain they will say you have to buy a new retail version as I don't think it's even legal to be using an Enterprise version at home if you no longer work for the company which bought it.
Alternatively you can pay an annual subscription to use Office applications online, it's called "Office 365":
message edited by phil22