Since November 2011 I have been using Sonar X1 Studio on Windows 7 64 – bit, but the program will not now start up.
I can pinpoint my last known definite use of the program to 21 November 2012. I may have opened it since then but cannot be sure. I can be sure that when I tried to use it on 16 December the program would not start. I received the following error message “The application was unable to start correctly (0xc000007b). Click to close application”.
  I have contacted Cakewalk support directly and I am still ‘talking’ to them. To date I have followed all advice but have not yet resolved the problem. With the assistance of a more technical able friend I have carried out a manual uninstall, including registry settings, then a full reinstall from original CD plus updates(using msconfig to stop the running of start up applications). Have also ran chkdsk which reported no problems and ran scans on Spybot search and destroy and Malware bytes.    
I’m currently awaiting further contact from Cakewalk.
I know that this forum is a place for the Cakewalk user community to get together and discuss Cakewalk/Music related topics and not necessarily resolve problems but I would welcome any input from users who may have experienced the same or similar problem and may have a solution.  I am hoping that I do not have to re-install Windows 7.
 

Regrettably I've been unable to find a simple answer to this problem and have therefore needed to re-install Windows 7 and start all over again. It is frustrating that I've been unable to identify the reason for the malfunction but at least 
Sonar X1 Studio is now working -  except that I now have a problem in that the playback of new files recorded (both audio and midi) come with a crackling noise. I've tried playback through my Edirol UA-4FX and using the PC built speakers and it crackles through both. This suggests to me that it is not a hardware problem. Can anyone offer advice please?
Alan in Cram 

Recheck your Buffers for Playback and Record, (Preferences/Sync and Cache)

Where are they currently set?

Some info on your system specs and interface/sound card will help us help you

Thanks Mike, it's simple (when you know how). Your advice led me to the Sonar online support "Configuring an audio interface". In the Playback and Recording section I set the Drive mode to ASIO (had defaulted to WDM/KS) and in the Playback I/O and Record I/O I set the Buffer size to 512 (had been 256).  I don't understand the technicalities, but it worked, no more crackling playbacks.  Thanks again. 
Alan   

Good morning Alan,

Glad ya got it sorted out  

Its hard to remember all those little things we had to do after a complete reinstall to make things run good.