Projects fail to open after recording tracks

I've had 4 projects so far that won't open anymore. All I get is the blank Sonar screen you see just after the you see the line move across in the transport window and just before the project is supposed open. I can click with the mouse all over that screen and can't even get it to white out. It's as if the screen is behind glass and I'm clicking on the glass. No drive activity indicating it's loading just a blank screen that you can only close from the task manager.
This is a big problem because all I am doing is either sending a track out to my preamp and compressor and recording it or just recording the normal way. The project works fine until I save and close it. Even if I save it as I record which I do it still happens. For now I made copies of all my other projects just in case. Luckily I have a backup of these projects but I lost what I did. There are no plugins involve just simple recording. I don't know what could cause such a thing. Never had this happen before. There is no way to recover the projects.
There is no support I can call or email. I sent an email on July 26th about something else and never heard a peep. The lack of support is not good when there is a serious issue.

Thanks AntMAn,
Opening the project in safe mode was the first thing I tried to no avail. Does the same thing.
The audio does play in other players such as Windows media player so the tracks are ok.
I copied the project folder to another location but that doesn't do anything. Obviously I can't do a save as or anything like that.
It's definitely not the hard drive.
All my other projects open and play fine. I just don't want to do any recording in them in fear of this happening.
Before doing any recording I make a copy of the project just in case the project becomes corrupted but if it does all my work is for nothing. I could copy the audio tracks in a new project but they don't line up and will be a pain to line everything up. There is no obvious reason for this to happen. Maybe it's the update and I should roll back and see what happens. I will give that a shot tonight.
appreciate all the suggestions that you can think of.
Thanks

Noel Borthwick [Cakewalk]
Do you have a second PC to try this on? If so copy the files over and open it there and see if it loads.
If the problem persists please upload the project to a share (with all the audio) and post a problem reporter CWBRN case number with the link in it. We can then see if we can repro it here.
BTW support would probably not be able to assist much beyond these steps anyway. For problems like this the first step is to remove system dependencies.

Thanks Noel. I don't have another PC but I am going to see if I can get to a friends house today and try loading it on his PC. Can you recommend a website that lets you upload projects? one of the projects is a little over 3gb.

It's not free, but Obedia.com has saved my butt a couple times with computer issues where the manufacturer's support would have been useless. The upside was after doing a remote desktop with them where they solved one particular problem, everything worked more smoothly.

Mosvalve
Thanks Noel. I don't have another PC but I am going to see if I can get to a friends house today and try loading it on his PC. Can you recommend a website that lets you upload projects? one of the projects is a little over 3gb.

Dropbox or google drive should work