calling applications

my project has to call some apps like regedit, scandisk, defrag,...
calling regedit works fine:
_spawnl(_P_NOWAIT, "c:\\windows\\regedit.exe", NULL);

...but when I try the same code with "defrag.exe"
or "scandisk.exe" it doesn't work...

why?
is there another way to call apps?

please help me.
thanks in advance.

Hi!
Try function ShellExecute(). See MSDN for details.

Dmitry Barashev.

You could also try the CreateProcess function.