I assume your 96 watter is 2G11 base?
looks (vaguely) like this:
[ O O O O ], four pins in a straight line?
1 2 3 4
wire it like this
[ O-O O-O ], pins 1 and 2 are connected and go to the "supply" leads,
1 2 3 4 pins 3 and 4 are connected and go to one of the yellow leads
instead of trying to connect all three wires from the ballast to the socket, tie all three together with a fourth in a wire-nut, and then run that fourth single wire into your socket
pins 1 2 and 3 4 don't really have a polarity, so just as long as you 'jumper' or short the first two and last two you'll be OK, each "set" controls the filament for each half of the bulb (think of it as a 6ft long bulb folded in half)
you 'might' be able to run all four leads into your PC
if you use a fan to draw air _over_ the bulb (don't blow air onto the bulb, this will cause cold spots) ... you'll get a bit more light and a bit less life ... or you could use the remaining supply lead to run whatever bulb you can find that runs at 13-32 watts (anything bigger will probably overload the ballast because of bulb length ... a 4x32 ballast can run approx 16 feet of bulb ... has to do with the voltage output or something)
we short the pins because an electronic ballast fires off a high voltage spike to "instant start" the bulb, vaporizing the little mercury drops (which are on the filament(s)) ... instead of heating the filiment to soft start the bulb like a PRS or RS (programmed rapid start or rapid start) ... if the pins weren't shorted, the ballast would vaporize the filament as well as the mercury, and burn out the bulb...
even with shorting the pins, the filament still burns a little each time the bulb is lit, due to something about electrons jumping from the plasma ... don't let this worry you, most PC
's are rated 10k to 20k hrs used on an instant start, assuming a 12 hour run time between starts ... if you were to switch the lights on and off rapidly to get that cool strobe effect your pleco's love, you'll burn up the filament in no time