ask to install message box?

how would i create a message box that when the destination folder is not a winamp folder it asks me something like "The destination folder is not a winamp folder. Do you want to continue?"

Command MessageBox:

MessageBox MB_YESNO "The destination folder is not a Winamp folder. Do you want to continue?" 

i know that much, but i want it to tell me that when winamp.exe is not in the destination folder

hi

sorry for my bad english...
use this

Function .onVerifyInstDir
IfFileExists $INSTDIR\Winamp.exe PathGood
Abort ;
PathGood:
FunctionEnd

the user can only install your software if the correct path is selected

You can mix both of them to create what you're looking for:

Function .onVerifyInstDir
  IfFileExists "$INSTDIR\\Winamp.exe" PathGood
    MessageBox MB_YESNO "The destination folder is not a Winamp folder. Do you want to continue?" IDYES PathGood
    Abort
  PathGood:
FunctionEnd