Welcome to the forums.
...I'm planning to reformat my computer OS.
And I need to get my mcafee virus scan enterprise v8.7i product key so that i can reinstall it after I reformat my OS.
VirusScan Enterprise (VSE) is licensed typically to a company or organization and this organization is issued a Grant Code.
The Grant Code holder can download licensed software from:
Typically, the Network/Security Administrator has this code. They are also the responsible party for handling support, installation, administration, etc. This is the person who has the software available for you to re-install after a reformat of the drive. If you are connected to the (corporate) network, you may be able to contact the administrator and they will push the installation to your PC or Laptop via ePolicy Orchestrator (ePO).
Contact your Network or Security Administrator to help with the re-install of VSE.