Check that the cable to the monitor has not come loose then.
The screen adjustment settings is likely a driver problem.
First download the newest driver for the monitor. On the desktop.. right click,properties,settings, advanced,monitor,properties,driver, update driver(select the location you downloaded it to)
To deselect interlaced. On the desktop.. right click,properties,settings, advanced,monitor...select 60Hz...click apply.....restart the computer.