I no longer have the brickwall.The problem seems to lie with the antivirus firewall. Many PCs are sold together with an antivirus software ready for installation (Norton; McAfee , generally)
Even if the new buyer doesn't install the ready-for-use antivirus in order to install another one , the Norton antivirus, for instance, is still there. To get rid of it you have to install it first and then disable it.
I found this out lately when I installed an upgraded version of Trend Micro PC-cillin : although I had never installed the Norton version on my computer it stopped the installation of PC-Cillin. Trend Micro warned I had to install Norton first and re-install PC-Cillin. When it comes to the stage when Norton stops the installation, the trend Micro antivirus takes over and removes all the Norton elements that could be in the way. Then you disable the firewall of your antivirus.
If you settings for LW are correct, if you have enabled your router and Windows security center to let through LW, the brickwall does not appear in front of the globe any more.