Try using psexec.exe
with the -i
switch :
psi.Arguments = "\\\\192.168.0.100 -i -u user -p pass D:\\app.exe";
or
psi.Arguments = "\\\\192.168.0.100 -i 0 -u user -p pass D:\\app.exe";
use 1 instead of 0 if you are using vista or higher. User desktop runs in session 1 in vista or higher.