The file extension ASC identifies so-called ActionScript Communication files. ActionScript is a programming language used primarily for controlling and creating interactive Flash applications.
ASC files are scripts written in ActionScript that are executed by Flash Media Server hosting software and serve various events, such as loading a Flash application, communicating with other servers, accessing other resources, or streaming media to control.
ASC files are simple text files and can be opened and edited with any text editor. Asc files can also be generated by the Adobe Media Encoder (included with Creative Suite) or the free Flash Media Live Encoder.
Most often resolving problems with opening ASC files is very simple. Just install an appropriate program that supports such files. All of the listed programs support ASC files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of ASC files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate ASC files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the NotePad++ applications is not on the list, select "Browse" option in order to manually locate the directory where NotePad++ has been installed.
Sometimes problems with opening ASC files may not lie with the application itself, but can arise due to other causes, such as: