screen freezes on restart, start after shutdown and even sometimes even during shutdown

[bhanuc]

Hi all,
I have Lenevo Y500 , with ubuntu 14.04 installed on SSD (only storage 
device) with Nvidia 650m with graphics driver version 331.49 . My system 
is fully updated and I update almost daily.
Some backstory-
Installed 14.04 , installed nvidia driver then after a restart unity 
launcher disappeared. I reinstalled nvidia driver( this had happened in 
13.10 and this has fixed it ) , no change so I instead of using 
compiz-plugins I decided to install ubuntu-gnome and gnome-shell. This 
fixed that problem but now  when-ever I restarted ,after the lenevo boot 
screen my screen freezes onto nothing and I have to force-shutdown and 
restart it again which instead of leading to that freeze screen it leads 
to grub screen and then ubuntu loads gracefully. But recently the system 
started freezing even while shutting down. There is no automatic error 
getting generated (so cannot log a bug ) nor did I see any fishy in my 
system log. Can anyone please help. I am kind of a newbie with all this 
so please let me know where should I start looking to solve this 
problem. I have attached all kinds of logs which I could find .
Thanks Warm Regards
Bhanu Pratap Chaudhary
-------------- next part --------------
A non-text attachment was scrubbed...
Name: logs.tar.gz
Type: application/gzip
Size: 277291 bytes
Desc: not available
URL: <https://lists.ubuntu.com/archives/ubuntu-bugsquad/attachments/20140228/c2f90cc9/attachment-0001.bin>