IMO its always a good idea to link to other threads you have on the same subject, it can reduce duplicated advice.
AFAIK the floowing is correct. Sorry if I make any mistakes/ommisions.
nVidia GTX 560 Ti-
Running new 'cutting edge' hardware on a older linux distro, or 'stable' linux distro is hit and miss at best. Dont know why you got a GTX 560Ti unless you are a heavy gamer, a cheap card would have been a better option. For a musician I would suggested $100-150 on a sound card and $50-100 on a video card, not $200+ on the video alone. But its done now....
You will need the nVidia drivers for HDMI sound output. AVLinux is based on debian stable. Debian stable has nVidia driver 195.36.31 in the repos. The GTX 560 Ti needs nVidia driver version 270.26 or higher to work, earlier drivers are not suported by that card. That is why running the script to get the nVidia drivers results in a blank screen....
trulan on the remastersys is wrong, you dont need a newer kernel for nVidia HDMI to work. The link he/she posted is specific to the GT520, not nVidia cards in general.
It might be best to ask the AVLinux forum about getting newer nVidia drivers than is in the repos. I *should* be able to give directions, but I'm not that familiar with that distro. So it would possibly save you a lot of effort and possible reinstalling to ask them before following any advice I might give you,
HP Officejet pro 8600 plus-
Have you got the drviers? hplip should do it-
You might have to d/l and install the file from HP. Before doing that, I'd try getting hplip and associated packages from whichever package manager you prefer or is stock with AVLinux.
Unlike windows, with many linux distros the CD/DVD drive wont show up in whatever file manager you are using unless you have a disc in there.