Visual Studio Installer: Service Pack & MDAC Check

i am using the Visual Studio Installer to make the setup msi file for my application. So far i have no problem but now there is a need for some new demands
1) The setup file is about 15MB of size. When i fix a bug it is really too difficult to make to a new setup and distribute this to our customers. Unfortunately here at Greece the broadband connect to the Internet is very limited:( . So the ideal is just to find a way to produce only something like Service Pack and send only this and not the whole setup file. Is there any way this to be implemented via Visual Installer or Visual Studio 6?
2) Some of my customers are using the Windows 98SE and there are some cases where the MDAC is not pre-installed so my application is not working (my application is a classic client - server style with a database file of Access). Is there any way to check if there is the right MDAC version and if not to install this, during the setup procedure?

Once the app has been deployed, if you change the exe, and don't add any more controls, then you don't need to use an installer. You can just give them a new .exe file.

If you use Inno Setup and Inno Script, there is an Automatic OS Updater that adds the right files to each OS. See www.*********** for all three.

At 99% the changes have to do with the code, and not with the controls. So if i follow your instruction is pretty enough, to give to my customers only the .exe file and just copy this to the corresponding programme file directory. Is there any possibility this file (.exe) not to be compatible with the others .dll?

If you add new controls or reference new .Dlls with the new .Exe then you will need to rollout a installation and setup package to deploy the OCX files that contain the newly added controls as well as the newly referenced Dlls.

If, on the other hand, ALL the changes are code related, then all you would need to do is supply them with a new .Exe