How do I reboot my Dell Inspiron N5050 laptop without the reboot disk?

I turned on my computer this morning and it didn't go to the same screen. I really can't explain it. My screen read, "Reboot and Select proper Boot device or Insert Boot Media in selected Boot device and press a key". I've Googled the situation, and it says to hit F8 several times before my Dell screen comes on. I've done that several times and it hasn't helped at all. I don't have the disk that reboots my laptop, and I just bought this laptop three days ago. Can somebody out there please give me some simple directions on how to fix this? Thank you in advance.