Help importing

I have imported a project to my Eclipse, and when I open up any class it gives me plenty of errors that say "The import **** cannot be resolved" and "String (or int or any other) cannot be resolved to a type". Then, I right click any of these errors and press "Fix project setup". This seems to fix all of the errors. However, when I run the program I get a new error that says that JRE System Library is Unbound and the program always runs with an error. How do I fix this unbound problem?

Once I look a bit more into the issue, it says that the java SE 1.6 is unbound. How do I "bound" it?

Moved from New to Java

db