No this is a win bug for many.((i believe Alec))..not just roland issues...I have had the lost audio/no sound thing since Jan first's week..I am not using roland audio...Another person on this forum, also had issues, and from there, the hunt for the problem came to be windows possible updates causing it with others also chimming in...I found a link to others having same issues after downloading updates for MS OSes.
 
If that is the case here.?..someone higher up snitchel head of some Knighted order, should ring MS and say something bright, while whacking them with a mace!....Just to keep things inline for us Ogres and minions of nil!
 
perhaps this:  http://forum.cakewalk.com/Help-All-IO-has-been-reset-no-audio-from-Sonar-m3159650-p2.aspx#3160094
 

Any word on the true nature or cause, or if solved?...please let us know...Thanks.
 

Not as yet in touch with Roland again frustrated as ever....will let you know

A few things since I have experienced this (with a Roland VS-700R interface):
 
• Do you have a number of virtual instruments in your project?  This can make audio die.  If deleting or freezing one solves the problem, that was the issue. (You may have to do the next step as well.)  I have a ton of memory, but sometimes 7 VIs kills my audio. Sometimes 13 is OK.
• Have you tried starting and stopping the audio engine?  It's the icon on the Control bar next to the MIDI plug symbol.  The audio engine thing looks like a sine wave.
• Do you have more than one project open?  That can make audio go nuts.
• If the MIDI buffer is too small, a MIDI track will appear to play but won't make any sound. (Preferences | MIDI | Playback and Recording | Playback.)  Mine is set to 1200.
• Do you have EZ Drummer 2?  Version 1 was OK.  Version 2 destroyed my audio.
 

I haven't examined all the posts concerning your problem but try  illuminating  the [FX] (Bypass all Audio Effects) button  up in the Control Bar. It's up there with the Solo, Mute, Record etc that do make global changes to the track content.  By so doing, I found, for example, that my CA-2A leveling amplifier was turned off because it had (supposedly) not been registered within the allowed period of time.