You shouldn't have to remove any wires. Make sure your computer is off, infact, just unplug it from the wall.
Now try and fit your GPU into its slot.
If you have to unplug some wires, do so, but REMEMBER where they plugged into.
Now when placing the GPU into the slot, a way to know it's in correctly is on the side(s) of the slot there should be these latches that should automatically start locking the GPU into the slot.
Once you feel like the GPU is in placd properly, make sure the latches are fully inward, locking the GPU down.
Now secure the GPU by screwing in a screw in the back section of your computer case, so the backside of your GPU where the VGA and HM or HD ports are to plug in your monitor, should be connected to you computer case.
Now locate your power supply, which is the piece inside the computer that the power cable from the walls electrical socket plugs into on your computer.
I believe the gtx 460 uses two PCIe power connectors, which are four prong connectors, so find two wires from you power supply that both have four prongs and plug them into your GPU.
Now close up your computer case, uninstall your old graphics card (I'm assuming yours is onboard, which means it came with your motherboard and is part of your motherboard) through your component manager.
Then install your new GPU by using the disc it came with.
Plug your monitor into your new GPU and you're done.