I have an i2353 AOC monitor, which has been working fine until recently, despite having not installed the driver or an HDMI cable It appears to be that there is a problem with the monitor, not the Windows 7 computer as when the monitor is switched on alone there are vertical lines appearing on the screen and the rest of screen is usually blank. Please can you help me to try and resolve this problem if there is a solution, or advise if I should perhaps instead get a monitor?