My computer cannot find the Operating System?

Hello,
I have a Acer Travelmate computer, and one day the computer froze while I while I was trying to attach an e-mail. After I shut off the computer, by holding the power button; the computer now goes to a screen that says:
PXE-E61: Media Test, failure, check cable
PXE-M0F: Exiting PXE ROM
Operating System Not Found

I don't know if my computer will ever get to the desktop again, but if anyone knows how I can recover my data, because I have much school work on this computer, it would be greatly appreciated. Thanks!