What is the function to use to run dos command?

I have a command button, I want to use regedit dos command. Once I click on command button it will load registry editor.

Instead of type in regedit in the command line. I want to know is there any function that will apply in command button to make it work.

You can use the Shell function for this. For synchronizing programs, ie running one when the next is done, use the Windows API CreateProcess.