Urgent Help Please!!!!

A friend of mine is in school now. Her H1 vise expired (6 years) before she was enrolled in school . Her I-485 was pending when she started school. The green card was sponsored by her previous company. Now, INS asked her for the most recent pay stub from that company to get I-485 approved. As she is in school and no longer working for that company, she could not provide such proof. As her last choice, she is trying to apply for F1 visa as she is a student now. My question is:
Is there any possibility for her to get F1 visa? What would happen if her F1 visa application is denied?
Thank you very much!