I'm trying to activate my disc but I get a message that it has been registered to another E-mail address. This cannot be as only I have been using it. My PC however has been updated. What do I do next?
I assume you are getting Error code -24, and are re-installing to either a new PC or one with a new hard drive.
Was the previous installation first registered with a different (old?) email address?
If so, you can still use that email address to register MEP. The address does not have to be in use/exist anymore.
If not we need more information:
Computer specification and program version, see this topic for what is required and please quote processor and graphics card make/model in full and the Windows build number if you have it- I would suggest you put this information in your profile signature so we do not have to keep asking for it.
Program full name and version number if you have it