c# file moving and deletion problems

Is there a reliable way of doing this? It seems that I am having problems
with the data files being used by 'other' processes, despite them being
custom to the application I'm writing. I'm sure that I never had so many
problems in c++ or Delphi, so is this a .net thing?

It seems that even having Windows file explorer open on the same directory
causes these problems?

I'm currently considering writing a C++ or Delphi DLL to handle the file
management for me as C# or just my lack of knowledge of it doesn't seem to
be up to the task.

RobP