Question

It should test if a specific port is open on localhost,if not,reboot.

It’s run in windows.

Answer 1

This should do it, tested on Windows 7 and working. Should work on all NT flavours:

function testPort($port, $timeout = 5) {
    if(!fsockopen('127.0.0.1', $port, $errno, $errstr, $timeout)) {
        exec("shutdown.exe /r");
    }
}

testPort(8080);