Whoa, whoa!
First, Web Server controls (part of .NET) do spit out just HTML - and you can set the compatability to work with IE, Netscape and more.
ActiveX controls can be hosted in the browser and mostly work with IE but also work somewhat with Netscape 6 and higher.
The Web Server controls do NOT need the 20mb framework on a client machine, only on the server. If youre not running .NET on the server, you obviously wouldnt need the framework there either (then you might just have ASP not ASP.NET pages).
As for being able to copy files and start an EXE you CANNOT use the Web Server controls as they dont have the permission to run on a client machine. An ActiveX control can do this, but usually (and hopefully) the user will be prompted to install and run your ActiveX control which youll want to have signed so that the user will have some idea whether to "trust" your code or not.
If you develop the ActiveX control, Id suggest using VB6. In that case, youll have to make sure the end-user has the VB6 runtime (which should be on just about everyones machine anyway).
An alternative to ActiveX would be a Java class. Im not real familiar with developing those classes, so I cant speak on the permission youll have but I would guess its the same as ActiveX (youll have to get prompted before having any Java code run that could harm a users machine, such as copying files or starting EXEs).
-Nerseus