Change difficulty to hard in The Witcher
Solution 1:
Well you can use the instructions on the page:
The difficulty settings are governed by the script in:
\DATA\SCRIPTS00.BIF\witcher_atr_abl.luc
Decompile this script using any utility that is listed in the LUC format article under the file formats category. Open up the resulting file in any text editor.
In the text editor you should be able to copy the settings for Hard into the settings for Easy or Normal (maybe back up the file in case you want to revert). Then just recompile it and stick it back in.
Edit: The save file format is laid out here. I'm not sure whether difficulty is stored as a "resource" or not. If the resource names are plain text, it shouldn't be hard to figure out whether that is the case.