You didn't state whether you purchased a slicer in addition to getting your radio tapped. If so, great - that increases the number of programs that you can run.
If you have a slicer - plug it in; tune your radio to a control channel and run the SLICER.EXE utility to validate your setup. Next step would be to run one of the "classic" Trunker programs to verify that it will work with your computer and OS.
For direct "slicer-free" sound input decoding you've got a few choices.
If you're a long time Trunker / Etrunk user then I strongly suggest taking advantage of updated Windows versions. It looks like you've got enough radios to place one under computer control for voice tracking.
If however, you want to download talkgroup data from RR (this does require a paid RR subscription) to avoid a lot of typing - you can choose Unitrunker. That program will eventually support voice tracking but it's not there yet.
Which ever program you use ... I offer the following - taken from the Unitrunker documentation as a suggestion for getting your computer configured for proper decoding.
Read this First
You've installed Unitrunker (or other program) on your computer. You've tapped a radio and connected the audio to your computer's sound input. Stop right there! There's a small chance you'll get lucky with things like signal levels and matched impedances. Odds are however that the signal level will be wrong - or that the apparent electical load caused by diverting discriminator audio to your computer causes the audio to be distorted. Maybe squelch stops working or speaker audio now sounds weaker than before. Before jumping in with both feet - save yourself some frustration by following this procedure. Download a software oscilloscope and run it. Tune your radio to a control channel and look at the signal on the 'scope. Do NOT use a real oscilloscope. You need to see the signal as your computer sees it. Adjust the signal level so that the signal is distinct but not clipped or chopped. If the resulting waveform looks distorted, you may need to place a buffer amplifier between your radio and computer. I highly recommend this. If you're having problems with microphone input, try the line input (or vice-versa). Once you've got a recognizable signal procede with the Unitrunker (or other program's) setup.
-rick