If you want to deploy both 32 and 64 bit versions of your app then obviously the best way to go is Any CPU compile. However, it is up to you to find out what "bitness" the OS is so that the correct runtime is installed. We provide the runtimes. We do not do support for installers, be it VS, InstallShield, or what ever. I suspect if yo google the subject of how to find out the OS "bitness", you'll find help on many different forums. I'd go and search MS first...
- Ludek