Can't use any browser at all

What firewall or security suite is, or ever was, on the system?

TCP/IP stack repair options for use with Vista and 7 and 8.

Start - All Programs - Accessories and right click on Command Prompt, select "Run as Administrator" to open a command prompt. [For Windows 8: <Windows Logo> + x - Command Prompt(Admin)]

Reset WINSOCK entries to installation defaults: netsh winsock reset catalog

Reset IPv4 TCP/IP stack to installation defaults. netsh int ipv4 reset reset.log

Reset IPv6 TCP/IP stack to installation defaults. netsh int ipv6 reset reset.log

Reboot the machine.


Open a (black) Command Prompt window:
Hold the Windows logo key and press r; in the Run box type cmd and click on OK.

Type the following command:

IPCONFIG /ALL

[Note that there is no space between the slash and ALL.]

[Press ENTER after each command.]

Right click in the command window and choose Select All, then hit Enter.
Paste the results in a message here.

If necessary use a text file and removable media to copy the results to a computer with internet access.