Ok, I am going to take a stab at parts of this...
You can get soundcards that handle both MIDI and audio. If you get a soundcard that just handles audio, then you also need a MIDI interface like a Midiman unit.
To connect the keyboard to the computer, you would take the out MIDI line from the keyboard and put it into the MIDI interface (like the Midiman) and then the out of the interface to the computer.
Then, you would also need a soundcard to handle any regular audio inputs you would need. Or like I said, the right soundcard can handle all of these together.
As far as the processor/equalizers go, you can hook them up between the keyboard if you are using audio, or you can hook them up from the computer to the processors, then to the recorder if you are recording to a hard disc. As for MIDI, I don't know if you can hook a processor up to a MIDI line before it gets to the computer. I don't think there will be a need for a driver for hardware processors, only for software drivers.
Ask if you need any other help!
Micro