Marion:
Your "account" is the email address, probably (but not exclusively) Hotmail or Outlook.com. Probably the email address you used to post this question.
See my reply to Bart about Office 365 "subscriptions".
When you bought the computer and "activated" the Office 365 (probably "Personal", 1-computer only) subscription you had to provide an email address AND a credit card. The subscription defaults to "autorenew". That is why you got the notice and the automatic
payment deduction. (MS loves getting money from you all of the time). You don't get anything from MS for the payment, other than the right to continue to use Office 365.
After your HD crashed, windows had to be installed. If you went to the manufacturer (ie warranty work) they would have installed a "standard" image that included an unactivated "free trial" of Office 365. That trial is now expiring.
The fix for your problem is simple enough (after I let you in to the secret). Use your email address to log in to the "MyAccount" site. Click on install. Here you should see a list of licenses you have and the computers. Your current computer should
be listed there. What you have to do is click on the "deactivate" link. This will allow you to "install" it again on your new HD. This is a slightly tricky part, in theory you should be able to use this "install" to link to the free trial. But I don't know
for sure if it will work this way. What I know works for sure is that BEFORE logging in to the MyAccount site go to "Programs and Features" and uninstall the free trial. Then the install from myaccount will install the appropriate Office bundle and activate
it on your new HD.
See my other reply for the links on "managing" your Office 365 subscription through the MyAccount site.