I've been working on a project for a while and decided to add VX-64 vocal strip to an audio track,suddenly I got the dreaded sonarplt.exe stopped working and my project closed.I know can't open that project at all without getting the same crash and I've lost a lot of hard work, is there anyway I may get it opened again.

Sonar safe mode:
http://forum.cakewalk.com/Open-Sonar-in-safe-mode-Solved-m2524512.aspx
 

I suggest you try this first:
https://www.cakewalk.com/Support/Knowledge-Base/2007013315/SONAR-X3-Full-VST-Rescan-Recommended-for-Upgraders
 
 

safe mode worked Thanks.