This is a small demo application that I wrote in PB8 to determine the processes currently running on my computer.  This demo makes use of the following Windows API calls found in either psapi.dll or kernel32.dll:

CloseHandle
EnumProcesses
EnumProcessModules 
GetModuleBaseName
GetModuleFileNameEx
OpenProcess

It could be used to easily determine if a process that is located at a specific file location is running or not.