cancel the .net 2.0 installation

Hi,
Before the software installation starts, get users' computer .net version to do version compare. If users' .net version is not updated, we will popup the messagebox to let user decide if downloading new version .net is wanted. Users choose YES to start downloading .net. Here is problems, if during downloading or installing .net, users clicks [CANCEL]. How do I know the .net process is cancelled to make the following software installation stop?
Thanks in advance.

1. Check download plugin ErrorLevel, for instance if you use nsisdl the return value is pushed to the stack (see included documentation).

2. Should be possible to check if installation failed with ExecWait variable exit code (see 4.9.1.4 ExecWait for details).

edit 🙂