Note: To properly execute the SIMx86 program you will need to copy the following two files to your C:\Windows\System directory (or whereever your windows\system directory happens to be): switch.vbx bivbx11.dll Without these files in the windows\system directory, the SIMx86.EXE program will not run. Note: You may have already copied this files in order to run the LOGIC.EXE program from chapter two.