Application Isolation and Assembly.LoadFrom
A thread on the Developmentor ADVANCED-DOTNET list produced a nice link explaining some of the intricacies of Assembly.LoadFrom. Here's a snippet:
However, there are a few intricacies to using LoadFrom that are useful for developers to be aware of. For example, you may run across situations in which calling LoadFrom doesnt load the exact file you expect. Also, understanding the order in which the CLR looks for a LoadFromd assemblys dependencies will help ensure that the CLR loads the correct dependency for your application.