John
I do implore you to upgrade. Sonar 2015 will run rings around Sonar 4.

but won't install on vista :-(

Doktor Avalanche
"until I can no longer find XP compatible hardware replacement parts. There is simply no money to keep replacing everything every few years."

XP is 14 years old.

some of my kids are 14 years old, doesn't mean i want to upgrade them!

bitflipper:  We disabled the UAC and when re-booting the computer the Sonar Wave Profiler starts on it's own asking if we want to let it do it's thing, We say YES, then nothing. It does not seem to complete so I assume it's locking up or freezing, but at least this is a step in the right direction because the audio hardware is now being detected. I can see the profiler running as a process, but we can't start the Sonar program at all now. I just can't understand why the profiler is starting on it's own upon boot up. I thought it was not supposed to start until you start Sonar for the first time?

I do recall that the profiler was a problem at one time, insisting on running when it wasn't needed. You're right, it's only supposed to run the first time you start SONAR, or if the interface hardware has changed. I think it was because of that annoyance that I originally switched to ASIO, which doesn't need the profiler. SONAR 4 does support ASIO, IIRC.

@pwalpwal I might have been lazy by using quotemarks (truth is I got pissed off with the forum functionality and my phone) but could you please edit your post, it makes it look like I wrote most of the above quote. Thx.

I would recommend Windows 7 - instead Vista.
Windows 7 runs much faster than Vista.
Sonar 4 works with Windows 7.

About 10 years ago I bought my first external audio card (Roland UA-4FX) with Sonar LE 4 included (same Sonar 4 audio engine); at the time I had an old desktop with XP and a more powerful gaming notebook with Vista. While I had no problem using Sonar LE with XP, it was impossible to use it in Vista due to horrifying sounds that occured after exactly 30 seconds (using Asio drivers) and I never solved the problem, while with mme drivers the issue wasn't present. Considering I bought the notebook mainly for recording, I sell it and bought a new one with Win 7 64 and this time my Roland worked smoothly. So, I don't know why, Vista was the culprit to me.
PS: in Vista my audio card was visible both in Sonar than in Windows.
Hope it helps

UAC may be only part of the problem. There are also changes in later Windows versions in how the installed programs are addressed due to limits on where a user (or the programs he is running under his account) can write files. Windows uses aliases for locations that older programs  expect to be installed to. If you can run the Sonar installer "as administrator," (which is definitely not the same as installing it from an administrator login account) you may have better luck. Also running Sonar "as administrator" is not the same as disabling UAC, since access of file locations based on user privileges is not the same as the UAC system, but was present in very early Windows versions. Running as administrator gives the program access to locations where it would not otherwise have permission.
 
http://www.computerhope.com/issues/ch001198.htm
 
So first try actually running Sonar as administrator, and if that does not work consider re-installing it by running the installer as administrator. If that doesn't work rub a penny on the monitor screen while chanting "evil out of the dead man's eyes" three times, and bury the penny in a graveyard by the light of the full moon .