If you prefer a more "manual" way using vi, use grep to find all occurences of the line and the number of the line where it appears in the file, for instance:
grep -n B.\ Gates /directory_to/filename
The (-n) will list all line numbers in the file where B. Gates is, with vi you place the cursor at the beginning of these lines and type: 'dd' to remove the line. You can also use the grep command and pipe it to "rm" to automate. Back up the file first and try on a copy as suggested above.
EDIT: Of course, both of these examples are bash and not vi, I don't think you can automate with vi. Type: 'vimtutor' in a terminal to take a little course for using vi/vim.