====== Office 365 check installed product key ======

Reference: https://support.office.com/en-us/article/Change-your-Office-product-key-d78cf8f7-239e-4649-b726-3a8d2ceb8c81#ID0EABAAA=Use_a_command-line_script

  * Run Command Prompt as adminsitrator
  * Run this command
<code>
c:\>cscript "c:\Program Files (x86)\Microsoft Office\Office16\OSPP.vbs" /dstatus
<code>

  * Check the last 5 characters of the installed product key
  * Remove the product key with this command. Do NOT leave space between "unpkey:" and the product key "XXXXX"
<code>
cscript "C:\Program Files (x86)\Microsoft Office\Office16\OSPP.VBS" /unpkey:XXXXX 
</code>

  * Then reinstall the product key 
<code>
cscript "C:\Program Files (x86)\Microsoft Office\Office16\OSPP.VBS" /inpkey:XXXXX-XXXXX-XXXXX-XXXXX-XXXXX
</code>

  * After input the new product key, better to run the dstatus again to check it.
<code>
c:\>cscript "c:\Program Files (x86)\Microsoft Office\Office16\OSPP.vbs" /dstatus
<code>

  * Then you could activate the Office software as usual by opening Word or Excel, etc.