annoying problem in 12.04

[Joep L. Blom]

I have since several months a very annoying problem in my Ubuntu LTS 
12.04. Suddenly the mouse freezes I can do very little. I can go to a 
terminal (CTRL-ALt-F1)and switch to other windows (not always) and it 
looks like mouse and keyboard are frozen. The only remedy is a cold 
start as restarting (using shutdown -r) freezes also.
I have all updates installed so it is up to date. I know that a complete 
new installed system - on another partition - could maybe an idea as 
this system is since 9.04 only upgraded to the next LTS. However, I am 
afraid that a lot of repairwork has to be done as many programs will be 
removed (especially those not in the repositories (e.g. wview).
I use not standard ubuntu but XFCE as I can't work with the windows 
mimic which is standard (I also cannot work with W8 which I have 
installed on a new laptop).
If somebody knows a solution and also how to bring the frozen system to 
life, I would be very grateful,
Joep