Strange... and very frustrating UA-1000 
Impossible to close Windows /shut down the computer when using the UA-1000 soundcard.
It could be any audio or video program using sound (Sonar, Soundforge, Premiere Pro... even Windows Media or VLC)
For example I can open Sonar and use it, but if I close it and try to re-open it (or any other program using the soundcard) ... Freeze!

All the drivers are updated
All the others sound devices are de-activated

Thank you very much for your help...

Open the task manager and see what is using it.

Thank you gbarrett....
But when it happens... so, everytime :-(  all is "frozen", even the task manager.
The cute little blue circle keeps on turning, turning, turning...

Hmm, in the drivers panel under preferences in Sonar, do you have "share devices,..." enabled?

Yes, it is enabled...

I keep on searching, and I'm thinking maybe the video card (NVidia GTX 570) could be envolved...

You probably don't want to be sharing those drivers. Uncheck the box and see if the problem goes away. What makes you think it's a video driver? I'm not saying it isn't that, but,... I've had an issue with my latest laptop - the video driver hangs up while Sonar X1 or X2 is playing/recording. It always comes back after several seconds, but it never shuts me down. So far it hasn't been to the point I want to take a couple of hours to track it down, but maybe I should. If you think it's video related, change your display settings to a different color depth or resolution. I'll work with mine tomorrow. Good luck!

Didn't had much time to do all the tests, but I think I found the problem...
It seems to come from the 4 NVidia High Definition Audio drivers installed by default with the video driver.
Once uninstalled, everything works fine!
I try now to permanently delete those drivers, because they are automatically re-installed everytime I start the computer.
Thank you again Gbarrett....