Hard drives do fail. If the BIOS can no longer detect a hard drive then it could very well be that the hard drive has failed (or someone wanted your hard drive and opened the little panel on the bottom of the notebook and took it while you were asleep). If the BIOS can't find the hard drive then I don't expect that Knoppix is going to be of much use. If your notebook has a recessed reset button somewhere on the bottom, you might want to try that. It really doesn't seem likely to help, but would not hurt at this point.

It could, of course, be that something in the computer that talks to the hard drive has failed. Before completely giving up I would suggest finding another notebook which uses a similar type drive (IDE or SATA) and seeing if that computer can see the drive. If it can (and I don't have high expectations), then Knoppix may indeed help ypu rescue files. Windows on the disk isn't likely to run on the second computer unless they are very similar hardware.

And you are right, the shop providing you "service" isn't likely to put forth any effort to save your data. Some like Best Buy are known for whiping the disk and reinstalling even when data could be saved, just because it makes their job simple.

You likely don't want to be asked this question right now but, has this experience taught you anything about the importance of backing up your important data?