Could you clarify your situation a little more.
Are you saying that your data files such as .doc, .txt have been changed to .pdf format? And what are the jlb files?
Also when did this problem start?, Was it after you reinstalled/updated windows or major software?
So your jlb files have now become adobe pdf files? In other words when you double click a jlb file now it launches adobe reader.
Ok, close all applications, then right click on one of the jlb files and select Open With. then point to Choose Program. In the box that opens look for the program that is supposed to open the .jlb files (JEWEL?). If it is not listed, click on the Browse button and navigate to where the program is located. Select it, then check the box "Always use the selected program to open this kind of file". Click OK.
This should re "associate" the jlb files with their original application.
Hope this helps. Let me know if there are still any problems.
Yes there is a way, and it depends on how long ago the problem started (one of the questions that I asked in my first post). If it hasn't been too long, system restore may be able to roll back your system to a previous state. Have you tried system restore?
If not and if you need help with system restore let me know.