I just want to make sure that you know. SONAR is incapable of ruining your amp. If it is not a fuse, tube or resistor, it has to be a setting of some sort. Have you tried a different USB cable, or a different USB port (do not use USB hubs)?
All the best.

Have you tried Windows Devices and Printers page to see whether the Fender amp shows up there, and if so is it disabled or set to "Do not use this device"? HAve you tried uninstalling then reinstalling the drivers for the Fender amp? I agree with those that say Sonar cannot of itself have disabled your amp, so it is likely a driver issue of some kind. That is, presuming it's not a hardware failure of some kind in the amp. I guess Fender's documentation provides troubleshooting help for that kind of thing.
 

Yuo guy are missing the fact, now his amp as a stand alone device is none responsive. It's dead, nothing to do wih software now. Its possibly just a coincidence that it died the day he tried to record to Sonar.  

Cactus Music
Yuo guy are missing the fact, now his amp as a stand alone device is none responsive. It's dead, nothing to do wih software now. Its possibly just a coincidence that it died the day he tried to record to Sonar.  

This.

That, I think, is a dead amp.

I doubt it's anything to do with software because I can't imagine how software or MIDI could damage an amp so it won't work at all. Not unless the amp's digital MIDI innards control everything and the firmware has been very badly written indeed.

I suppose there's a possibility that the volume could have been turned down by the amp responding to whatever MIDI continuous controller sets its volume, if it responds to that kind of MIDI message at all, but if that were the case it would still show up as a MIDI/audio device. And any firmware that keeps the last MIDI settings it was sent and ignores the front-panel volume etc. would be such a nightmare for users and support staff alike I can't easily imagine any reputable long-standing manufacturer being daft enough to ship such code in the first place.

I suppose the amp could have turned into a big paperweight during a failed firmware update or similar, that kind of thing does sometimes happen.....

Whatever, I suggest contacting Fender's customer support and seeing what they say.

I looked at the schematics. If the 5 volts supply blows a fuse the amp is dead. All the front panel controls for volume, tone etc, feed into a micro processor that controls everything else. Essentially it's a computer with a tube output section. Anything that could bring down that processor could bring down the amp.
 
If the USB activity was an added load it could cause problems. USB is 1/2 amp and the supply is fused at 2 amps. That leaves 1.5 amps for the CPU and other 5 volt loads. I really hope the OP gives us the final results on the cause.

My amp has revived!!!!  I was about to give up on it.  My guitar instructor suggested that I remove the back panel on the Super champ to see if any tubes were out.  I did that and also unplugged and re-plugged the line out cable.  All the tubes looked to be working. At least all were glowing.  I then tried the factory reset one more time.  Much to my surprise it worked this time.  I don't really understand why it revived....but I'm thinking while moving the amp the day that I installed Sonar, I somehow jostled the line-out cable.....but that's just a guess.   In any case, I'm glad it's working again. It's a great sounding amp.  Thanks for all of you comments and suggestions.
 
Marty
 
 

Glad you got it working again  

Molarman
It's a great sounding amp. 
Marty

I have an SC X2 head but not used usb.
The advantage of usb as I recall was that is had speaker emulation on what is on line output.
Line output does not use tubes at all - it's all a digital chip.
 
So what I do is use a Radial JDX di-box that connect over speaker and emulate speakers that connect through mixer - and you also get the power tubes in the circuit.
 
Or if you don't bother with tubes, use line out through soundcard normal way - and you won't have the issues associated with having multiple soundcards. Then use separate speaker emulation from various plugins available. It could be impulse responses for speaker cabinets or otherwise from many vendors, Izotope Trash, Two Notes Torpedo(also available as plugin), Waves GTR and similar.
 
Multiple soundcards is a mess. And usb in this case most probably don't give you asio drivers usually used for recording daws.

When looking at the Fender info on the amp there is no mention anywhere regarding drivers. 
I have a Blackstar and the USB is mainly for controlling the amp with a computer. I use the line out which works just fine, even though it's only 1/8" TRS. Our singer has a Fender Champ that has the USB and we've never used it, I just use the Line out to the PA. My guess is the quality of the USB interface and / or drivers on these budget amps is pretty pour. 

Some of the cheaper Fender amps are considered non-repairable by Fender. If it acts up in warranty they replace the amp. If it's out of warranty they sell you a new one. No spare parts are available from Fender or a repair center.