Monitors don't always need separately downloaded drivers, but it would help if you reduced the ambiguity about which monitor you have. Your subject line indicates an Asus p236h, even though p236h is actually an Acer model number, but your message body indicates you have an Asus VH242. For an Acer p236h, you can select your monitor on this page and download a driver:
http://us.acer.com/ac/en/US/content/drivers