Note - mine is plugged in via USB, but you could try plugging your in via MIDI and see if it works that way.

If you use MIDI cables only, Sonar will only see the MIDI interface, not the Radium. That may work, but the USB connection should be better. 

 Okay, i went to the m-audio site and somehow downloaded the Axiom 49 driver and that got my computer and cakewalk seing the device! But not working right still. Soafter unistalling via device mgr, and uinstalling the other M-audio driver for another M-AUDIO KEYSTATION I borrowed quick, and then reinstalling the original driver I've installed 100 times, i am a little bit further but still not there. I can see the device, the cpu does too. Cakewalk akcknowledges it better than ever but still doesn't work, tried other synths and vst plug-insetc... nothin...
https://skydrive.live.com/redir?resid=4FC6C0C0D9CB4FE4!210&authkey=!AO1y4Y7ag5e7T_I
https://skydrive.live.com/redir?resid=4FC6C0C0D9CB4FE4!211&authkey=!AAxalCLSKGSnLMc
 https://skydrive.live.com/redir?resid=4FC6C0C0D9CB4FE4!211&authkey=!AEeUSd5f11lcbRk
 
 

This is the driver you should be using:  Radium49 04/27/2010 5.0.0 (PC) Install M-Audio Legacy Keyboard 5.0.0.exe



Make sure you have the 32-bit version is you're running Windows 7 32-bit or 64-bit if using 64-bit Windows. 
I would uncheck the MS GS Wavetable synth. Instead you should insert a softsynth, such as the TTS-1. Then insert a MIDI track and select the TTS-1 as the output. Leave the input set to none. Arm the track and record something. 

You haven't mentioned what soundcard you're using. Are you using the built-in soundchip? Also, what mode are you using in Preferences-Audio-Playback and Recording? Try ASIO first, then WDM, then MME. 

Hey!  Firstly,  thanks for all the help. 

My audio/sound thing in device mgr says:
 
Sigmatel High Def Audio Codec

My headphone jack is broken so I gotta plug in this Radioshack USB adapter that appears toi be namd under "playback devices"as:

7-4300054 Gigaware USB Audio

There is also the Speakers:

SigmaTel  High Def Audio Codec  (I have it disabled and set USB Gigaware as default)

Then also under playback there is the Digital Audio S/PDIF set as default "communications" device, whatever that means, has a phone in the icon so maybe old software...

DEVELOPMENTS:

I have no idea why But I was working on my drum track manually using piano view, having given up on the M-audio radium 49, and also the new one that now I know to be an unnecesarry addition to studio, the Keystation 49e. I got thinking a new device had to be the answer, and both were plugged in and installed and powered on for some reason and all of a sudden the Radium 49 worked as good as ever before! 

I checked the keystation 49e and as it always had since taking home, only played some cymbals on some of the black keys, so  I thought: "whatever" and have been working hard on getting as much done bfore it crapped out again.   So for the last like, week and a half i've been using my laptop like one typically does, so unpugging the usbs and audio usbs to take it with me places degragsl, restarts, diff usb ports etc... everything worked as it should.  But today for some reason(despite all working last night) it is all screwed up again!  I haven't touched a thing (not even a restart). but now after trying everything again I am positive  (to extent of my knowledge of course lol!)  that this is yet another "one of those things"....  I guess the philosophy that goes: "Sometimes **** just don't work and ya gotta start over" must be accepted as truth, but I know...

There is ALWAYS a solution, it all comes down to to where my level of expertise ends and how much further the knowledge is of person solving the problem for me
I have a degree in Graphic design and have been around computers since a a couple years prior school so i have been experimenting and learning since 1994 on my own and since i was in 1st grade on the apple IIe.  I now have recently over the last year attained my 1st laptop and now am on my 3rd and am able to and actually HAVE HAD to take them all apart and put them back together. Desktops as well. My point is I am not an expert but prob much higher level than avg person, however as a musician I only am NOW paying attention to this MIDI thing that I have known about as long as i can remember but never got to  intrested until my dad's midi strat confused me when i tried to plug in.  That's my history.

SO now I am seeing the legacy driver in Midi devices but I have only the Radium plugged in so i ho[pe uninstalling drivers and reintalling them will fix or maybe just scew the keystation 49e for the radium is better anyways.  I hope to be able to hage themboth and use keystation for drums and radium for synth and avoid all the headache I forsee while switching between the two instrument s in future but for now bahgy steps,  i'll be back (likely stressed out lol!)

If its working, that's good, but you've got some issues with your selection of equipment in my opinion. The Sigmatel soundchip is not a good platform to run Sonar. You are probably using MME mode which has its limitations. Also, the Radio Shack USB headphone cable is a bad idea (anything from Radio Shack is a bad idea.)

Oh, well. Have fun anyway. 

Yeah thanks guys i don't see any point in making you run on circles with me.   I just entirely uninstalled all the m-audio, midiox etc... and reinstalled the CORRECT drivers for the keystation 49e and radium 49 and now it only shows the keystation and only the mod wheel has any effect on the program so ...to hell with it, i'll tweak on it more and get it working, then set a restore point make a template file etc.. to insure I have a fighting chance next time.  But the goal is new computer again , or an external soundcard like thing.  Not familiear too much with them, seen em, used em, but they worked on those other peoples computers so not an expert....
 I got a laptop thru craigslist and the headphone jack was busted which is HUGE to me so that is the reason for usb heaphone but yea.   I'm sure there is a cheap usb external driver or mixer or whatever you'd call it right?  I gotta use the USB thing for sound other than the laptop speakers so i'lll need some device.  I got a powered samson MDR 624 mixer a few yrs ago but i don't think that can help, it may have been made prior to the new home-recording popularity.  Any final suggestions on  that note?