lost power and now computer won't boot

Hi -

I have a Gateway SX2840-01 desktop running Windows 7 Home Premium 64bit. We lost power a few days ago and now when I try to turn it on I get this message:

Reboot and Select Proper Boot Device or Insert Boot Media in Selected Boot Device and Press a Key.

I do not have a backup/restore disc for this machine but I do have a Windows 7 CD and it can't fix my problem. Keeps saying it can't see the hard drive - device cannot be found.

I have tried to change a few things in my BIOS based on what I've read online but I'm afraid I'm just messing things up more. Is there a way to know exactly how my BIOS settings should look for my PC? Is there anything I can run so you can get a better idea of my problem?

I really want to be able to backup the HDD at the very least, but ideally I'd like to fix this problem so I can continue to use this desktop. Can you please help?

Thank you!
Meko