Hello and sorry you're having problems. Unfortunately when the screen is cracked, it requires complete replacement of the LCD panel- which costs 80% of what the TV cost when new. Additionally the vertical lines and solid black circle indicates the inner LCD has leaked and the panel is bad. Whenever we see a screen with a bad or cracked panel, the TV is not repairable as the cost of the new screen is so expensive and the entire TV needs to be rebuilt from the inside out to replace it. In other words, it costs more than the TV did when new to replace the screen.
However, there are two options here. One is to find the EXACT same model number LG (The LCD controller is matched to the screen), with a blown power board, or a different fault, and salvage the screen from it.
Or two, contact http://www.shopjimmy.com to see what they will give you for the set as is, as they purchase TV's with broken screens and then sell the other boards to TV repair shops and DIY'ers.
Other than that, I'm sorry for the bad news and wish there were a quick fix.
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