If you are installing on a computer used for multiple tasks then check for conflicts in the communication ports. For info on ports read https://help.qlik.com/en-US/sense/3.0/Subsystems/PlanningQlikSenseDeployments/Content/Server/Server-Deployment-Ports.htm
If you have vpn-clients running on the machine it could trouble the environment, look for Cisco vpn, forticlient, vmware etc. Even in the vpn case it is often port conflicts causing the trouble.
Note: Qlik Sense is not fully supported on win 7 as far as I know, last I checked win 7 was only for demo and laboration purpous.(please correct me if I'm wrong)