[Lakshmiveda]

After accidental hit my computer with my hand
I restarted again and a window came with all the options to restart but didn't do it even in save mode. So looking for some info in the net, I found a video where it shows how to resolve this problem (since apparently its very common) In this video tells you to go to command prompt, and rebuildbcd. I did that and i restart and now i just have a black screen with a message: Operating System Not Found.
I download Windows 8 and I save it in a external hard drive, I went to BIOS to change the boot preferences and now is in external device as a first option.
Restart again, press f12 as it says and now the same black screen with this message: Media test failure, check cable...
My laptop is a Sony Vaio Machine name: VGN-FW270J. Bios version: R1090y0, System memory: 4096MG. Hard dick drive (which i can still see listed) 320GB
Thanks in advance for your help. And please try to read the for me its very important not to lose any file. It is to late already?