This has been discussed many many times in this and several other forums. You might want to read through the forums or search (a good key word might be "recover"), as I certainly am not going to duplicate all of the information everyone has already posted.

In brief, the answer is maybe. There have been many cases of people booting Knoppix and recovering files when XP will not boot. Buit it should be obvious that if your windows partitions have taken enough damage then you might not be able to get the data that you want from them. Assuming that Knoppix can boot and see the files and it's only Windows itself that can not, then how to recover depends on where you can put the needed files, the size of the files, and what resources you have available. Some people save files to USB flash drives or other external USB devices. A very popular way to save recovered files is across a network to another computer running either Windows or Linux. Some people with a high speed connection have saved files to other locations on the Internet. Some people with a FAT patrtition (not NTFS) have saved files there and some have even installed a second hard drive just for the file recovery. What you do will depend on your particular resources, but it is good that you are thinking about this now rather than later when there is a need and you are more likely to be in panic mode.