Turbo C# is a discontinued Integrated Development Environment (IDE) from Borland that came in two versions, Explorer and Professional. It uses the C# programming language to develop applications for WinForms and ASP.NET.
The free Explorer edition, which had a fixed IDE targeted towards student, amateur, and hobbyist programmers is no longer available.
The Professional edition had an extensible and customizable IDE.
References
Turbo C Sharp Wikipedia(Text) CC BY-SA