Some people find themselves unable to reinstall Windows 7 onto their machines, because they might have lost their Windows 7 backup images, backup external hard drives, and Windows 7 installation/recovery DVDs. Of course, they can make a backup of their current working Windows 7 machines, but what if their current Windows 7 working machines are rigged with computer viruses and malware? Another option is to go buy a brand new Windows 7 software in stores, but that is defeating the purpose of having a legitimate Windows 7 key in the first place (i.e., it came with the computer when you bought it).
Don’t sweat, I’ve found a website/blog post (http://www.mydigitallife.info/download-windows-7-iso-official-32-bit-and-64-bit-direct-download-links/) which lists available official Windows 7 ISOs for you to download and then burn them onto CD/DVD so you can reinstall Windows 7 onto your machines. Obviously, you need valid Windows 7 keys to activate your Windows 7 installations, eventually. Usually, there will be Windows 7 keys physically taped to your machines’ cases — look for the keys and you will find them somewhere on your machines’ cases.
For your information, I used VirusTotal’s “Submit a URL” scanner to scan for computer viruses and malware on these downloadable links of Windows 7 ISOs, and I’ve found nothing dangerous. So, as far as I know from using VirusTotal, these downloadable links of Windows 7 ISOs seem to be safe and innocent. Nonetheless, you may want to use your Linux machines’ ClamAV to scan for the downloads from these links for extra caution. Good luck on your reinstallation of Windows 7!