Intellisense not working

I am opening files from a server ASP.net and the VB codebehind files, and my visual studio is not working correctly, Intellisense is dead and if i right click the "Go to defenition" option is disabled. These files are not part of a solution.

This is strange though because it was working properly yesterday. If I create a new project the intellisense works great, yet opening this single file it fails.

I have tried to re enable intellisense by resetting visual studio, I tried editing the text editor settings so that Auto list members and Parameter information are both checked. I even tried installing ReSharper and nothing worked. I have rebooted twice and even tried copying the file to a local drive to work on yet nothing.

Does anyone know why this is happening and what I could do to solve the problem? Im working on a rather complex problem and intellisense would make it a lot easier.