Create an application that restarts itself after n-seconds once
Batch, 34 28 bytes

timeout/t %1
if %1 neq [] %0


Input time in seconds as the first argument. If no argument is present, as well as after restarting, it spews out error messages (follow both commands with 2&gt;NUL to get rid of them). The new instance opens in the same window (OP said it's allowed).