Find out if an application is currently running

[IlseH]

I created an application which opens several other windows applications by pressing a button. These applications, however, should only be opened once. Is there a possibility to find out if the application is already running, so I can perform a test on that.
Thanks in advance

 

[dsi]

What type of programs? What language did you write the program in that opens the other applications? This can be done using the Windows API, but my sample is limited to VB.

 

[IlseH]

The application is written in Progress 9.1B. It opens the programs CorVu and Crystal Reports. I already know the solution to the same problem in Access using VB, but now I need to find the solution for progress.