Why won't Windows start?

I’ve been to all the sites to help out with removing the program however they all request that I change the LAN settings. I do this but seconds later they get automatically changed back. Whenever I open a file the message: “Application cannot be executed… file is infected” Therefore I am unable to run any programs such as Task Manager in order to counter this virus. Can someone please help me out because it seems I am defenseless. Thankyou