Problem with Visual Studio 2008 Setup and deployment projects type

Question

We have implemented a C#.NET app. That we are forced to distribute it to our customers with a little computing and IT knowledge via a CD. We are forced also to accumulate prerequisites such as .NET Framework 3.5 and Sql Express 2005 with our app. On the CD because of low speed internet in our country and also our custormers low comutational knowledge as mentioned above. To gain this goal we selected VS 2008 setup and deployment projects project type. After overcoming a lot of problems, now we are faced by another problem that after spending a lot hours searching different web pages we did 'nt gain a suitable solution to it. The problem is when the Sql Epress 2005, already is installed on the machine which we want to install our app on it; our app. throws an exception by message like "sql server could 'nt create a user instance…". Of course we know to resolve this problem manually we should delete folder "C:\Doument and Settings\UserName\Local Settings\Application\Sql Server\Sql Express"( Sql Express Directory ) and then restart the system but problem is our low computation knowledge customers; what if they want to reinstalling the app?!. Thus we must automate the above solution ( deletion the directory of Sql Express 2005 ). In search for solution, I decided to write a batch file which delete the Sql Express directory while uninstalling the program and then reboot the system. Of course my solution failed because of problems such as not having sufficient privileges to run commands such as 'Shut down -r' in the batch file and also some times when trying to delete the Sql Express directory We faced by an error message such as 'some of containment files are being used by other application …' and so on. Know we are concerned with occurrence of this problems on our low knowledge customers ' systems which are hundreds kilometers distant from us and our sole media to guide them to get the system working are phone lines.

Can you tell us please if there is a better way to overcome our problems? Or are the any good solutions which resolve my solution problems so that our low computational customer could experience a comfort and silent installation a way from technical problems according to our used technologies?

In advance, thanks a lot for your short and useful solutions ( against my question! )