Case fans are very, very cheap. Depending on where you buy them, their price can go from $2 to $4 online for one. But I find it odd that the wires would just "come loose" from moving the PC, fan plugs are very sturdy and don't unplug easily.

Before doing anything, place the computer on a small table (away from the floor), unplug the power plug, open the side of the case (there should be some screws in the back of the case) plug it back in and turn it on. Look around to see any "dead" fans.

Turn it off, unplug it again, touch the metal side of the case so you're grounded, and double check that the cables are secured. Try turning it on again. If that works then you don't need to buy new fans.

Edit: What could also have happened is that the fans are way too dirty and won't spin anymore. It happens to me all the time. If that's the case, then replace the fans.