Windows Power Essentials Tips & Tricks
You will typically find keys.dat in the following directory:
The simplest solution is to delete the keys.dat file entirely while the game is closed. When you launch Vice City next, the engine will automatically generate a fresh, factory-default copy of the file. You can then remap your controls safely. Controller Mapping Issues
Would you like a ready-to-use in C++ that adds chord support? I can provide the hooking logic and file format extension.