After updating a system today, Ubuntu's doesn't display correctly. The desktop now looks like this. It was working properly before.

I had to use the terminal to run synaptic package manager, so I could view the update history; which is as follows:

Commit Log for Wed Nov  7 11:50:36 2012

Upgraded the following packages:
linux-image-generic (3.5.0.17.19) to 3.5.0.18.21

Installed the following packages:
linux-image-3.5.0-18-generic (3.5.0-18.29)
linux-image-extra-3.5.0-18-generic (3.5.0-18.29)

Prior to this issue, the last active driver was nvidia-current-updates, version 304.51. I tried using the nvidia-current driver, version 304.51.really.304.43 instead, but the problem persists.

I tried running nvidia-settings from terminal, so I could try configuring something, but the application informs that the Nvidia driver is not being used.

As the x-swat repository has nothing for Quantal, I desperately used the unstable x-edgers repository & upgraded, but to no avail; so I purged it.

The display should normally be full HD, but the only available resolutions now are 1024x768(4:3) and 800x600(4:3).

The system is Dell XPS-L702X, with NVIDIA GeForce GT 555M, and 17" screen.

How can I fix this problem?

Update: I tried using the Nouveau third-party driver & this fixes the issue. However, if you have any idea how to get the Nvidia drivers working properly with the latest kernel, please share; as I've noticed some videos playing very slowly on the system, though I'm not sure exactly why.