I'm not sure what you mean by install.
Is this connectivity problem both with wireless and Ethernet or just one or the other ?
Other than network adapter drivers and antivirus programs, DNS servers can impact connectivity.
I use Level3's DNS servers instead of my ISPs which are 209.244.0.3 and 209.244.0.4
You can try this to see if it makes any difference by going Start - type ncpa.cpl and press enter - right click on whichever adapter you are using and select Properties.
Uncheck the box for (TCP/IPv6) as that can cause connectivity issues then click on (TCP/IPv4) and select Properties.
Check the lower button for Use the following DNS servers and in the top row of boxes type 209.244.0.3
Tab down to the lower row and type 209.244.0.4
Check the box to Validate settings upon exit - OK - Close and that will invoke the troubleshooter which should come back as no problems found and then reboot to see if you have the same problem.
If using wireless and you have a yellow alert on its taskbar icon, right click on it and select Troubleshoot problems to see what it reports.