For "If not, what API call will close the application?" You can use WMI:
loWMI = GetObject("winmgmts://./root/cimv2")
loProcesses = loWMI.ExecQuery("SELECT * FROM Win32_Process WHERE Name = 'AcroRd32.exe'")
For Each loProcess in loProcesses
loProcess.Terminate(0)
Next
"The five senses obstruct or deform the apprehension of reality."
Jorge L. Borges?
"Premature optimization is the root of all evil in programming."
Donald Knuth, repeating C. A. R. Hoare
"To die for a religion is easier than to live it absolutely"
Jorge L. Borges