Study to Evaluate Using Nelfinavir With Chemoradiation for Non-small Cell Lung Cancer

Inclusion Criteria: * Histological diagnosis of non-small cell lung cancer that is Stage III (T1-3, pN2, M0) NSCLC in whom neoadjuvant therapy is recommended. * Must have had a mediastinoscopy to determine nodal status and potential resectability * Must have enough tissue from the biopsy for tissue marker determination for correlative studies * Negative metastatic work up (FDG PET/CT, brain CT or MRI) * No prior thoracic radiotherapy will be permitted * Age 18 years or greater * ECOG performance status 0-1 (Karnofsky at least 70%) * Normal organ and marrow function * No known HIV infection * Not pregnant * Ability to understand and the willingness to sign an informed consent document Exclusion Criteria: * Patients requiring a pneumonectomy * Patients who have had chemotherapy or radiation therapy within 4 weeks prior to entering the study, or who have not recovered from adverse events due to agents administered earlier. * Prior thoracic radiation * Treatment with any other investigational agents. * Known metastases * History of allergic reactions attributed to compounds of similar chemical or biologic composition to NFV * Patients receiving drugs contraindicated with NFV will be excluded. * Uncontrolled, intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study compliance. * Pregnant or lactating women * HIV-positive patients on combination antiretroviral therapy