Sonar sound output and other applications audio

 I am just getting up and running with Sonar, and am getting the gist of things slowly, and am having some issues with audio out configuration. One way I am teaching myself Sonar is to watch Youtube videos and follow the steps outlined in the videos in Sonar as they play. The problem I am having is that very often the sound in the video playing back in Firefox will drop out when I open or build a Sonar project. When I close Sonar it will come back. I have tried to edit the Sonar preferences on 'Playback and Recording' to 'Share Drivers with other programs' but it doesn't seem to always work. The weird thing is that sometimes I can get Sonar sound out and get sound out in other applications at the same time, sometimes not. My understanding of computer sound drivers/playback devices is not strong at this point. My hardware is a Intel G-35 Chipset motherboard (Q6600 processor) with onboard audio (no add on audio card yet). Is there a configuration solution to this problem? Or would buying a discrete PCI sound card be necessary to give me enough audio output channels to listen to the video tutorials with Sonar application running?

 Yeah, I thought that more audio channels might be the solution. I was thinking of buying a cheap generic PCI sound card for now because I do not have any spare PCI-E slots on my motherboard. I will build a new system based on a new IvyBridge CPU and associated motherboard this Spring/summer and get a PCI-E soundcard to go with it. I was looking at one from M-Audio, the 1212M PCI Express. http://www.amazon.com/gp/...0938631&pf_rd_i=507846

I don't know where this will end up but I am needing some help deciding what kind of software to get to do what I need to do.  In a nutshell--our church has an organ (Rodger's 797) that plays MIDI files--these are files that an organist has actually recorded on our organ or another Rodger's organ.  These files are emailed to me from all over the USA--wherever I can find an organist that can make a recording.  I then download them to my computer and put them on a flash drive to use with the Pro-Filer that is attached to the organ.  The music is played through the Pro-Filer and sounds as if there is an actual organist playing our organ--the stops light up as the song is played.

What I need is software in which I can take the MIDI file (recorded music) and put it in the software and correct some of the notes that are incorrect or the timing isn't good or the tempo is too slow or fast.  I would also like to be able to copy a verse of the song and create another verse.  I would also like to be able to see the notes on a music staff so I can follow along as the hymn is played in the software and then see the incorrect note.

Do any of you have any experience with software that would do what I need.  Our church is small and can't afford to spend money on software just to find out if it will work or not.  I really need someone with experience with editing MIDI files to let me know if I am just dreaming!!  Thanks for your input.