Cordlez, I had exactly the same issue trying to get two Nova-T's running in a rig. The answer isn't simple, but it worked for me.
Essentially what happens is you get two "ghost" tuners in the registry and recording/ playback acts wierd (I could record two channels and watch a third, but if I hit record on the third it would say i only had two (or sometimes one) tuner.)
Anyway, here's what I did.
The rig had one nova-T already installed and set up. Channels scanned orderd etc. I backed up the HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Curr entVersion\Media Centre\Service\Video\Tuners part of the registry just in case.
Now under HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Curr entVersion\Media Centre\Service\Video\Tuners you will find a few keys, two of which are hex numbers. the second of these when opened will contain your two tuners - both identified as a hex number. Open one of the tuners and find the key called User Sttings. Export this key - call it user.reg or something.
Now delete all the tuners from the registry - trust me here - you won't lose all your channel setups.
OK, now power down and install your second Nova -T and reboot. Check the registry and you will see 4 tuners are present - no ghost tuners. Now run the MCE Tuner Config tool, name each tuner and enable all four for MC use. Close the app.
As a sanity check, reboot and recheck the registry. You should still only have 4 tuners listed.
Now the fun begins. If you look in the User Settings for each tuner, you will see they are empty. You need to recreate these. If you rescan & so on all your series records will be broken, so I did it manually.
For each tuner, export the User Settings registry key, call them tuner1.reg, tuner2.reg and so on.
Background - the only difference in the User Settings key for each tuner is the hex number that identifies the specific tuner. What we will do now is a find and replace to make each tuner have a User Settings key.
Now, go back to the user.reg key you exported earlier ( the original User Settings key) and edit it. Also open Tuner1.reg for editing. Find the hex identifier in use.reg and copy it to the clipboard. Go to Edit|Replace and paste the hex number into the Find box. In Tuner1.reg find the hex identifier and copy it to clipboard, then go back to user.reg and paste it into the Replace box. Then click "Replace All". Save the edited file as Tuner1A.reg.
Repeat this process for tuner2.reg, tuner3.reg and tuner4.reg.
Once all four tuners are done, import Tuner1A.reg, Tuner2A.reg,Tuner3A.reg and Tuner4A.reg. Reboot.
Check the registry, you should still ahve only 4 tuners and all the User Settings keys should be populated.
Now try to record 4 channels - you should have 4 tuners running.
You can now set the record and watch preferences for each tuner as described
here.
I have assumed you are fairly comfortable editing the registry and are familiar with it. Naturally, back up before you start, just in case.
I know this is rather long, tedious and not intuitive, but this is the ONLY way I could stop phantom tuners appearing in the registry when two Nova-T's were installed. It's a pain, but once done it works fine.
Hope this makes sense, if you're not sure just ask.
