The question, more or less, is:
How do you run whosthere.exe into a remote machine using psexec dettached from any console and leave it running there collecting hashes?
the answer is:
psexec's -d switch basically makes it run whosthere.exe and exit.
whosthere's -o switch specifies the name of the file containing the list of unique credentials collected.
and the -i switch makes whosthere.exe run in an infinte loop looking for new
logon credentials and storing them on the file specified by the -o switch.
Remember, of course, you will probably need to specify the -u and -p switch to psexec, or you can do from your machine something like
net use \\
and then run psexec.
Also remember, that if you want to use whosthere-alt.exe, you can't use psexec's -c switch (I think), because whosthere-alt.exe also requires the pth.dll, so you will probably need to copy whosthere-alt.exe and pth.dll to the target machine and then run psexec without the -c switch and specifying the path where whosthere-alt.exe and pth.dll are located.
Hope it helps!.