Now that Band in a Box comes on its own hard drive, has that changed anything, as far as what computer to use?
No, that has nothing to do with it. The PGM hard drive is just another external storage device, it's not processing anything. The processing is done by your CPU in your computer.
Keith, you said you're not very technical and I can certainly see that's true. I sympathize because about 15 years ago I was right there with you. I decided to get into digital audio and knew absolutely squat about any of it. I could barely spell MIDI much less understand what it was.
First, Bob's Mantra: "Midi is not audio, audio is not MIDI, ommmm."
Once you understand that, the first question is what exactly are you recording? Are you using the Ketron as a sound source for Biab? If so that's for Biab's MIDI tracks, the Real Tracks/Drums are all audio, not MIDI so the Ketron is not doing anything with the RT/RD's
Next is do you sing, are you wanting to record your vocals?
Next do you want to record anyone else like a singer, a guitarist, whatever?
Right now you have a laptop and a Ketron. The Ketron is a synth that accepts a MIDI signal and converts that to audio. Go back to Bob's mantra and understand that. It converts MIDI to audio. How do you hear or record the audio? To simply hear it you take the RCA audio jacks out of the Ketron and plug them into your amp or studio monitors. To record that audio you have to run those RCA's into your laptop and then the audio FROM the laptop goes to your sound system unless you want to listen to everything on the little crappy laptop speakers. The headphone out's from the laptop can sound pretty good, you could use an audio adapter to run the audio from the headphone out to your sound system.
If your laptop has a line out but no line in then you need something to get the audio into the laptop. The only way is to use a USB interface. That interface plugs into your laptop using it's USB port, it's the USB that carries the audio from your Ketron. The interface has inputs for your mic or any instruments (which are audio inputs). That means you need an interface with two audio inputs for L and R stereo. Those come from the Ketron. You could use something as simple as this:
Behinger Line 2 ALL this does is run the audio out from the Ketron to a USB line into your laptop. Personally I think it's a waste of money because you'll realize you want some other inputs too like a mic for example. But if all you want is a way to get the audio from the Ketron to your laptop then this is all you need plus a couple of 1/4" to RCA adapters. Then use the headphone out of your laptop to your sound system.
This is enough of a lesson for the moment. Let us know exactly what you're trying to do.
Bob