ShellExecuteEx performs an action on a file that can be an executable file or a document. However, when it infected by malware, virus, and other potentially unwanted programs during the process of its installation, ShellExecuteExfailed;code1203 would haunt you. In fact, ShellExecuteExfailed;code1203 arises from virus that is able to insert its code into you files as well as change their names. As a consequence, ShellExecuteExfailed;code1203 is really can bring your certain problems and inconvenience.
If you want to remove it, there are two removal guides-manual removal and automatic removal guides in virusremovalexpert.blogspot.com.