I don't think there is any such thing as an adapter to allow an LGA 1151 CPU to adapt to LGA775. I once had a QX9650 which was the quickest at the time, lol. That system has long been retired. Do your RESEARCH. First work on your budget. Choose the platform you wish. ASUS offer the skylake Z170 pro MB. Good for gaming. Choose your processor and other Hardware (partpicker is a good place to go) Post your system specs and we can look at it.
We owe our existence to the scum of the earth, Cyanobacteria