Updating files

What would you suggest I use to update some outdated files on users computers? Some of the files I need to update are dll files (system32) and some datafiles (program directory). Some of the dll files are registered dll's (with regsvr32) and others not.

The program were packaged with PDW but if I use it again to update the outdated files I get a second instance of the program in Installed Programs under Control Panel.

If I write my own update program; Would I need to unregister the registered DLL's, copy the newer file and re-register the DLL's or can I just copy the newer file into the system32 directory? If I need to re-register the DLL's, can it be done programmatically and how?

You would need tp copy the new dlls into place and then register them. I am not sure about the unregister part. I do not think it is needed, but it is possible that if you do not there may be some let over clutter in the registery. I do not think it would be a problem even if it is left behind though.

The other issues you may run into is file in use requiring it to be copied as part of the bootstrap and of course the user not having access to copy files into this location.

Maybe I'm missing something but this problem have been already solved by other install packages, like InstallShield (cost) or Inno Setup (free) for starters.

Thanks guys. I'll look into Inno first and see if I can get it to do what I want.