How to make installation not replace files?

I'm packaging my application using Visual Basic's built-in software "Package & Deployment Wizard". This works okay and creates a working installation.

The problem occurs when someone that already has some controls installed (i.e. MSCOMCTL.OCX) or some VB6 runtime file and has another program in the background USING them, the installation will report an error "File already being in use, Ignore/Retry/Abort".

Now should the user wisely enough choose to Ignore this dialog, another message comes up warning him about the dangers of ignoring files and that the whole app might stop working and perhaps even the whole system etc.. Should he attempt to cheat faith and press Yes, another file in use will cause the same error again and the user will think "It's better to Abort".

At least that's what three of my beta-testers said. And I can understand them, the installation is supposed to provide assistance to beginners, right? Like install any missing dependencies, not just replace the lot.

If not, then how is making a .CAB any better than just making a .ZIP-file with all the required dll's and program files?

I'm confused about this, i think it's only me that doesn't knwo how to use Package & Deployment Wizard correctly. Could anyone point me in the right direction? Orperhaps there's another type of installation software more suited for this?

Moved.

If the files are in use, then something else is probably running. Installations usually request that you shut down all processes. It's best to use Add/Remove programs from Control Panel, also.

Yes, but most people dont shut down all applications, as it isn't in practice necessary. Or they forget many like stuff running in the background, in tasktray, etc.. I Myself run a service called FreeProxy which is a proxy server written in VB6, which can't be turned off "on-the-fly". So stuff like this will conflicvt with the installation.

Any tips on how to make it just "skip" existing files by default (if they are the same)?