Microsoft used to make the .iso installs easily available, but took the links down earlier this year.
I've tried using the new download tool with legitimate serial numbers (Win7) and get bizarre options. The next step after it accepts the code is to select the language; it shows French and a dozen other options, but no English. So yeah, not an improvement...
If you still have the DVD you are likely better off just buying an external USB optical drive and install (or make your own ISO) from that. Any generic one should work; don't need the fancy Apple version. Good luck!