I've been working on a project plan for a long time and in the last few weeks it started not responding a lot. Now, I can just click in a cell or highlight a random row and it doesn't respond. Sometimes it lasts several seconds, most of the time it lasts minutes or shuts down altogether. It is extremely frustrating. I literally can't get through anything. I took an older version of the file that seemed to work fine and redid a lot of work on predecessors and durations and save this new copy - this one is now doing the same thing. I don't know if it's a problem with one piece of data, or if the file is corrupted, or if there's some antivirus or licensing programs going in the background that is causing this. How can I find out and fix this without starting from scratch? I've googled it to death.

Sometimes I get an Application Hang error (in event log viewer) saying that WINPROJ.EXE stopped interacting with Windows and was closed. Other times, I get an Application Error showing the faulting app name WINPROJ.EXE and faulting module name MSVCR100.dll or KERNELBASE.dll. Any ideas?

I am using Project Professional 2013 and Windows 7.