Waiting Function

Hello,
I try make a exe,which is waiting for a process and then do it stuffs
But the problem is the while,is block the execution of the exe.
The exe is a program which includes dialogs
So,i ask if there is a another way to make make a waiting function and then the stuffs will be

get all processes (maybe by using Process32First and Process32Next) and when u find a process with the desired name break the loop