What chip did you buy? What motherboard do you plan to use it on? If the cpu and motherboard are compatible, you didn't make the most egregious error, because at least you can have a computer that works. If the board you ordered is for skylake and not haswell, then yeah, you made a big mistake. Has the cpu been taken out of the box, put onto a board and had thermal paste applied? Then you probably won't be able to return the cpu. Have you contacted Newegg about your error?