|Don't remove any folders or files that you have not put there yourself. It's OK, for example, to remove pictures, documents, videos, music that you have added. If you hack away at system folders or files you will mess up the computer.|
You can also go to "Control Panel > Programs and Features" then uninstall any non-system program you have added. This (unlike removing files and folders) will completely remove programs including their registry entries.
An alternative to the above is to do a complete Factory Restore so that the computer is as it was when purchased. This will then require Windows Updates, Flash Updates (etc) and download/installation of any important programs you wish to put back.
As per response below - it all depends what this D drive is. Let us know. The general drift of the above still applies if it is just a data drive, except that everything on it will be what you have added and know about.
Always pop back and let us know the outcome - thanks
message edited by Derek