- Obtain win 7 installation files.
This site is a mirror for all the win 7 ISOs (in several languages), includes links to MSDN file hashes (after downloading, I used HashTools to compare hashes).
Also there is a tricky possible solution here.
- Format a USB as a installation disk using Rufus.
- Install OS, install critical drivers from hardware vendor website, use these instructions to bring computer up to date.
- Install Chrome, firefox, VLC, Microsoft Security Essentials, f.lux