Desktop GUI gone after upgrade to 15.04

I just upgraded from 14.10 to 15.04 and now when I boot into the system I get a blank screen. ( it looks like a graphically generated black screen)

 I get no feedback from it at all no blinking cursor. I can ctrl-alt-f1 into a console and everything is working just fine. I have an NVIDIA graphics card, but my understanding is that if there is a driver issue it should default back to the open source NV drivers. After some research, here's what I found.

 1 - There is a problem from 12.10 to 13.4 that someone spoke about there being an issue like this that had to do with running off of a Solid state drive. ?

 2 - I'm wondering if there is an issue with LightDM. when I was installing I got an installation GUI pop up that warned me to make sure I had grub installed as there would be a boot problem with light DM. I have grub installed so I clicked continue.

 3- there is always a myriad of people complaining about NVIDIA problems in X11. but I'm not getting anything but a black graphics screen... as in it appears to be a graphicaly generated black screen with x running .... just nothing showing .

 I know someone is going to ask me for my x11 file or logs. I'm at work posting this hoping someone can just give me some Ideas on this.

 Thanks

 Tim