Enable/Disable Windows Proxy

http://ozansafi.wordpress.com/2009/07/05/enabledisable-change-ie-proxy-by-scriptprogrammatically/

To disable proxy:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"ProxyEnable"=dword:00000000

To enable proxy:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"ProxyEnable"=dword:00000001

To change proxy:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings]
"MigrateProxy"=dword:00000001
"ProxyEnable"=dword:00000001
"ProxyHttp1.1"=dword:00000000
"ProxyServer"="http://ProxyServername:80"
"ProxyOverride"=""

Copy these to a .reg file and double click on them to do the trick. The good part of doing it this way is that it works on every IE version(well, I haven’t tried any IE lower than IE6 and it is able to change it without even opening up anything.