you could install the update then open cmd and type ipconfig /renew and see if that helps. Do you know your way around then event logs?

The latest security update for Windows Vista - Security update KB2744842 - stops my internet explorer from being able to connect to any websites. I've tried removing the update and sure enough, my explorer goes back to working as it always did. The update has now automatically installed 3 times and every time it has stopped the explorer connecting. So far the only solution is to remove the update via System Restore. Any ideas?

you could install the update then open cmd and type ipconfig /renew and see if that helps. Do you know your way around then event logs?