NEED HELP!!!! COMPUTER!!!?

Hi I have a GIGABYTE Netbook but then I clicked F9 and it opened "XPRESS RECOERY 3 Lite". Then just of out of curiousity I clicked "Restore". Then this is what appeared "Overwrite MBR? HDD MBR data has been modified, HDD will be overwritten if you choose YES." I chose YES and then I realized it was, I think, reformatting my hard drive. I stopped it before it finished but when I try to turn on my computer it won't turn on. A blue screen appears with words then directly disappears. I need help a lot. My important school work is in there.