Bring a large pot of lightly salted water to a boil. Cook pasta according to package instructions and drain.
While pasta cooks, melt butter in a large skillet over medium heat. Whisk flour into butter until smooth. Pour in milk 1/4 c. at a time, whisking constantly until smooth before adding more.
When all milk is incorporated, add frozen shrimp scampi, and reduce heat to medium. Cook 5-8 minutes, stirring and turning shrimp often. Shrimp will be pink and C-shaped when cooked through. (Be careful not to overcook!)
Turn off heat, and stir in parmesan until melted. Serve shrimp scampi alfredo over hot cooked noodles.