I don't as a rule recommend websites but I've found a good one for anyone that needs image files for installs. Most of this sort of site are a nightmare for ads and add-ons but this seems clean and easy.
Obviously you need to use your own licence but if you've lost your orig install disk or never had one give http://getintopc.com/ a try.
They have versions of everything I can think of for Windows, Mac and Linux, incl Operating systems (as far back as win 95), Office (to 2003), Visio, CAD, Development, Education etc. Just download and burn as a bootable image to a USB or DVD. It's also handy as a one-stop-shop for things thay allow a 30 day trial and you know you'll only need it for a short time, like diagnostics and repair software.