It's quite unclear what "updating a calendar" exactly is, and how it possibly could have this effect. Can you tell more?
Anyway, the first diagnostic is to try this TV on another desktop/laptop and another (HDMI?) monitor/TV with this desktop to see if it's an issue of the TV or the Dell.
If it turns out, it's in the desktop, first try System Restore back to before you did what you did to cause it.
I'm using win 7 os Dell opt 330 desktop . everything was fine up until a few hours ago . I updated my desktop calendar and now I'm have ghosts on my screen . I attempted to adjust my refresh rate but anything other than 75 hertz is not supported . is there something I'm overlooking ? thanks