Keep the WD-40 well away from the fan if you want to have any hope of fixing it. WD will attack any remaining lube in the bushings and prevent you from adding new. Someone suggested light oil, do that. You should be able to find "Zoom Spout" turbine oil at most hardware stores, it's an oil for lubricating motors, unlike some other Water Displacement products that like to cosplay as lube. This paragraph brought to you by Water Displacement products, for when you absolutely, positively have to kill an electric motor.

The likelihood of disassembling a small motor like this, replacing the bushings, (which you're going to source...where?) then getting it back together aligned well enough to spin, as a home gamer, is pretty close to nil. Sorry, that's just how it is. I've rebuilt larger motors successfully, but the little ones just aren't made to be worked on.

Your best bet is to try to source and replace the motor or just bite the bullet and replace the unit. Get it at Menard's if you can, at least you'll get some store credit for other stuff, provided you remember to send in the rebate.