I'm trying to get my digital piano to use virtual piano software, but the software wants to hog the hardware audio card for itself. Is there a program that can be used to force it or map it to the software driver? This can be done in linux with a script, but I don't know how to do it in windows.

I'll put my specs in my sig momentarily.

Can't see anything in your sig.
Can't help you if i don't know what digital piano, what software piano, what hardware audio card we are talking about.

I don't know, maybe it will show in this post.

It's all software I've tried. Art Vista and Ableton Live are the ones I've most frequently used.

I think the issue is that it conflicts with other programs that are using the audio driver.

hmmm...try this? http://vidance.com/asiomulti/asiomulti.html

Thanks for that program, but I don't even know if it solves the problem as I can't even open art vista anymore.

It gives me a message, "physical memory getting low" then asks me if I want to continue then loads a moment and then says "could not load sample no big enough memory blocks available" I have 12 friggin gigabytes, that should be plenty. It can't possibly be my system not meeting hardware requirements.

I see that the Art Vista Piano uses Kontakt Player.
Maybe it is because you accidentally disabled disk streaming in the player settings ?

I also see that the Piano plugin requires "11 GB free disk space (6 GB for VGP2 library + 5 GB for downloaded installation archives)", so maybe if the streaming is disabled, it tries to load it ALL into your 12GB RAM ?

Did you try REAPER ?
From my experience it is the host that runs VST(i) plugins most efficiently and uses the least amount of RAM for its own purposes.

Which OS are you using? If it's a 32 bit OS then you won't be able to access more than 3-4GB of memory per program no matter how much ram you have. To access your full 12GB you need to use a 64 bit OS or look to see if there are any workarounds for your software.

Hmm... Well, I went to options and selected 'active' under 'direct from disk options' and that solved the loading issues.

Then I switched from the ASIO driver to directsound and now I play music and have it open at the same time. Although, I do remember there was some problem with this, but it's working for now.

I didn't think it would be that easy. But thanks for all your help.

Well, it's working, but my original problem still remains. I cannot use any other audio program, whether it's Firefox or winamp, and Art Vista Virtual Grand Piano at the same time. Often times, if I have been using my PC for awhile (I never shut down only sleep), Art Vista will just lock up and refuse to open or close and the only way to get it to work is to restart my PC. When it does open properly all other sound output is muted in some way.

Anyway, I'm convinced that this is because Art Vista wants direct access to my sound cards hardware, instead of mapping through the software layer like Winamp or Windows Media Player or Internet Explorer does. I cannot possibly be the only person who has this issues in using audio products similar to virtual piano software. I don't believe that this issue is limited to the particular application I am using.

There has got to be some way of mapping virtual instruments through the software layer.

I am 99% sure your problems come from using the standalone version instead of a vst dll plugin.

Try these two freeware hosts:
http://www.hermannseib.com/english/vsthost.htm
http://www.tobybear.de/p_minihost.html

I'm sorry but that's not a good solution to my problem. I don't want another program. I just want a virtual piano software that will allow other programs access to my sound card.

At least try it.
I don't know what is your level of knowledge about using VSTi plugins like Kontakt sample player inside VSTi capable hosts, so i am sorry if i underestimate that knowledge.
A properly written standalone audio app will not take your soundcard all for itself, but if it does you have an option to use the often included dll VSTi version with a host that will most probably use the soundcard just like it should.

There is also another solution that will almost look like what you most probably want (based on my understanding of your english).
http://www.hermannseib.com/english/savihost.htm
Place the savihost.exe in the folder you installed your Art Vista piano in and rename it to the name of the dll file, but keeping the .exe extension.
Then run the exe.