Kubuntu 13.04: Impossible access

[nemrod]

Hello, after several posts since yesterday in several forums without any responses, I try here with the hope of a solution:
After updating kubuntu 12.10==> 13.04, I have problem of White Screen!
Impossible to access something. Impossible to do something. Trying to reboot, and with grub unsuccessfully repair damaged pckg, impossible to access to the previous version 12.04, 12.10, 11.04, 11.10. I did not overcome the problem. Does it exist commands line ?
I suspect the nvidia driver loading, sometimes the mouse seems to be freeze. With the live cd, I can access kubuntu 13.04 without problem.
I use kubuntu since 2008, I use to upgrade it after each new distribution, this is the first time I see a such mess. What should I do ? Any Commands line ?
Have you a solution please ?

Regards.

[Teunis]

Please mention how far you do get, is this white screen at the grub prompt, at log in or later?
Grub should offer the option of a recovery mode (sometimes via Advanced options).

An easy test is to see what happens after you rename the ~/.kde directory, this can be done from a Live CD.
At log in a new /.kde will be created.

It sounds like you have an install that has been upgraded many times, this is known to eventually cause issues and you might be better off with a fresh install.
A fresh install is really easy when you have your /home on a separate partition.

When you don't have a separate /home partition this is your chance to make one.
In all cases start with making a back up of this /home.