Hello W源源,
Welcome to the Microsoft Community.
You are advised to use the following tools to uninstall office.
https://aka.ms/SaRA-officeUninstallFromPC">https://aka.ms/SaRA-officeUninstallFromPC
And then open cmd (administrator), input:
cd C:\Program Files (x86)\Microsoft Office\Office16
( If the path is displayed incorrectly, input: )
cd C:\Program Files\Microsoft Office\Office16
( input: )
cscript ospp.vbs /dstatus
( Find the last displayed KEY:XXXXX ,and input: )
cscript ospp.vbs /unpkey:XXXXX
Then download office at the following link:
https://officecdn.microsoft.com/db/492350F6-3A01-4F97-B9C0-C7C6DDF67D60/media/zh-cn/HomeStudent2021Retail.img">https://officecdn.microsoft.com/db/492350F6-3A01-4F97-B9C0-C7C6DDF67D60/media/zh-cn/HomeStudent2021Retail.img
Then open the App Store and click on "Redeem" at the back of the office app.
https://answers.microsoft.com/zh-hans/msoffice/forum/all/answers/fb9344cc-a56f-41e9-a5b8-f65ac7885b6a">https://answers.microsoft.com/zh-hans/msoffice/forum/all/answers/fb9344cc-a56f-41e9-a5b8-f65ac7885b6a

If you have any questions, please feel free to reply.
Best regards,
Pondsi
你好,w源源,欢迎访问社区!
建议使用以下工具卸载Office:
https://aka.ms/SaRA-officeUninstallFromPC
然后在任务栏搜索框输入 cmd 点击“以管理员身份运行”,在窗口中输入:
cd C:\Program Files (x86)\Microsoft Office\Office16
,如果提示路径不正确,请输入
cd C:\Program Files\Microsoft Office\Office16
然后输入(/前面有空格):
cscript ospp.vbs /dstatus
将看到接近最后的一行信息结尾显示KEY:XXXXX
然后输入以下命令(冒号为英文标点):
cscript ospp.vbs /unpkey:XXXXX
(XXXXX是上述显示的5位数字字母XXXXX)
然后从以下链接下载Office2021:
https://officecdn.microsoft.com/db/492350F6-3A01-4F97-B9C0-C7C6DDF67D60/media/zh-cn/HomeStudent2021Retail.img
然后打开应用商店,库,设备预装,点击Office后面的“兑换”,完成激活。
https://answers.microsoft.com/zh-hans/msoffice/forum/all/answers/fb9344cc-a56f-41e9-a5b8-f65ac7885b6a
Pondsi