Hi @ivoperetto 

Just to confirm you had a working/bootable windows 7 machine, you installed Webroot on it and restarted and it no longer boots? 

Can you boot into safemode and uninstall webroot and see if they boot again?

We can help you do all of this by submitting a ticket or calling our support line

Webroot Support:

Submit a ticket 24/7/365

Call 1-866-612-4227  during the week Mon - Fri 7 AM to 5:30 PM (MDT)

Note: When submitting a Support Ticket, Please wait for a response from Support. Putting in another Support Ticket on this problem before Support responses will put your first Support Ticket at the end of the queue.

Yes I already boot in safemode and unistall webroot.

I need now to understand how to install webroot in these two machine

If removing Webroot in safemode allows the computers to boot normally and re-installing Webroot causes them to no longer boot normally then something is going on with the machines. I would take a look at the logs or our support team can do this for you and resolve your issue after getting more information

I had this with one PC months ago running  windows 7 and to be honest we never got to the bottom of it, thankfully the vast majority of our client base are on 10/11 though. The machine in question was a workshop machine that sadly couldn't be upgraded due to incompatibility with a 3rd party piece of software