how to build a patch for existing installer

I build an installer, and it is deployed. I need build a patch to upgrade old files with new files. Please help me. Please help me how to do it.

I am using Visual Studio 2010 Ultimate.

Thanks.

Visual Studio doesn't support creating patches, but you can always create major upgrades:

• increase your Product Version, changing the Product Code
• keep the same Upgrade Code
• modify your installer project and build it
• when the new version runs, it will automatically detect and uninstall older versions

If you really want a patch (MSP), I suggest using a free or commercial setup authoring tool.