Did this happen after a sudden power outage or after you turend your computer off improperly? You sound to be having the exact same problem as I am currently, where the partition table bits on the hard drive were wrote incorrectly having the drive show as RAW instead of NTFS if you right-click the drive and go properties what shows up in that windows?
I mentioned Linux as it is another OS you can get it on live cd search google for Linux live cd distro you will find many different flavours, linux is capable of reading the RAW partition format allowing you to recover your data and copy it off to another drive, or you may wish to fix the partiton table with partition table doctor however I can not guarantee this method will leave the info intact.
go to
http://forums.techguy.org/hardware/8...tched-raw.html that is my post look it over