Can't start Windows Vista (hard drive isn't recognized?)

[arlab]

Hi.

Suddenly, my computer freezed (just like it has been doing for some time now).
When I restarted it, the computer asked for the Vista DVD, so that it could repair some files (I couldn't even boot into Safe Mode). I put the DVD inside the drive, and choose the "Repair your computer" option, but it reports that no Vista installation is found...

I then boot into the Rescue and Recovery environment to see what's going on.
The System Information detects everything except the Hard Drive (it reports "Not Available" for the fields "Hard disk free space" and "Hard disk capacity"). I also can't see the harddisk in the option to backup the files to a pen (the pen is recognized, though).
Just to be sure, I run PC Doctor and my hard disk passes all tests.

What's going on? How can I fix this? Help.

My harddisk is: hitachi hts722020k9sa00 fde ata device

[arlab]

I chose the "Repair your computer" option and selected "Next", even though, no hard drive appeared in the list. Luckily, it worked, anyway. Weird.

All is well, now.

[i.thinkpad]

You are very lucky, but your hard drive is unstable now. If I were you, I would backup important file/data in no time.