Kalim-
When you boot up Knoppix, there are some icons on the desktop, i.e. My Documents. Click that, and it will show a window with an upper left portion similar to the attached screenshot. Click the hard drive partition at the bottom of the list e.g. "11.9 GB Volume" in the attached screenshot (probably different in yours.) Note: if you have multiple "Volumes", the biggest one is probably where Windows keeps the C drive. Once you have one clicked, there may well be a slight delay before the contents show up on the right.
Now the fun part! You should probably just search for the file you want by name; if it was in your Windows "My Documents", try right-clicking the "Documents and Settings" folder and choose search, enter the file name etc. Once you locate the file, right-click it and choose Copy. Now plug in the flash drive or whatever you want to Paste the copied file to, and then click that new icon, find the location on that drive where you want the file, right-click it and choose Paste. Repeat as needed.
Enjoy!
Krishna![]()