VFP encrypting the exe will not stop decompilation and ReFox can be bypassed as has been discussed on the UT many times . I think currently KONxiSE fom XiTech is probably the best option but its also probably crackable.

>If you brand it through ReFox, then ReFox will stop decompiling at a specified spot. W/o branding, ReFox will happily decompile your entire program. Other decompiling programs may ignore the scheme that ReFox uses. Can't think of any way to encrypt a program in a way to make it impossible to decompile. XORing the contents of the EXE file w/ some random data would indeed make it practically impossible to decompile the program -- with only one minor side-effect -- this also renders the EXE useless ;-).