If my wife has moved out the house, can she prevent me from selling it?

As long as you're technically still married and both of your names are on the title and mortgage note, the house is still jointly owned by both you and your wife and you cannot sell the house without her consent.  However, in the event that you do obtain her consent and sell, you absolutely must split the proceeds from the sale, though you do have the right to withhold whatever her contribution would have been over the four years that she was not paying her share of the mortgage or the maintenance/upgrades.