Fan sockets popped out

Any electronic shop will solder back that socket on the board for cheap but if you want DIY you'll need a solder iron with a fine tip. Clean the socket and it's board location with 90% isopropyl alcohol, let dry, apply a SMALL drop of super glue under the socket and align it over the 6 solder pads where it was before it was snapped off. Hold it firmly in place until the glue is hardened. All the 6 board pads should be well aligned with the socket legs (4 at the front, 2 at the rear). You don't really need to add solder just briefly touch each solder pads with the fine tip of your solder iron. If there's not enough solder left on the pads to do a good contact you'll have to add some and use flux to prevent bridges between the pads. To solder back this type of socket you cannot use a hot air station. The socket would melt on the board. Now to check if everything's fine use a multimeter to check continuity between the solder pads and the metal pins inside the socket.