Could not load file or assembly ‘itextsharp, Version=5.5.0.0, Culture=neutral, PublicKeyToken=8354ae6d2174ddca’ or one of its dependencies

I have used itextsharp library to generate pdf in my asp.net web application. It was working fine untill today when suddenly my laptop on which the application was running in the debug mode went off. When I switched on my laptop again and tried to run the application I satrted getting this error:

Linq join on two values

Suppose I have a list of {City, State}. It originally came from the database, and I have LocationID, but by now I loaded it into memory. Suppose I also have a table of fast food restaurants that has City and State as part of the record. I need to get a list of establishments that match city and state.