Question: I run Ubuntu 12.04.4 LTS 32 bit version and recently took the option to take the HWE upgrade from Update Manager. Now either the computer freezes or I go into a low graphic mode similar to the Terminal. I believe this is because I have an old Nvidia FX5600 graphic card. If I run 3.13.0-32-generic in recovery mode I can use my computer. My question is can I reverse out the HWE upgrade or will I have to reinstall the OS from scratch using the original CD?

Answer: 
The core problem is that the HWE update doesn't install the headers for the new kernel. These headers are necessary for the NVidia driver to build its kernel module. To fix it, simply install the linux headers and then reinstall whatever nvidia driver you're using:

```
sudo apt-get install linux-headers-generic-lts-trusty

```

**Note:** this is for Ubuntu 12.04.5, if you're using a later release, it's going to be `linux-headers-generic-lts-RELEASENAME`.

Then when you reinstall the nvidia driver and reboot, you should be fine once again.
I have met with this same problem and I tried a lot of methods. The method given by Sylwester does not work for me. The method by Joecool almost work for me but I have to change some parameter. I type:

```
sudo jockey-text -e xorg:Nvidia_331

```

the restart the computer and everything will be find. And how can I know it is 331, I type:

```
sudo jockey-text --list

```

and find out that 

```
xorg:nvidia_304 - NVIDIA accelerated graphics driver (Proprietary, Disabled, Not in use)
xorg:nvidia_304_updates - NVIDIA accelerated graphics driver (post-release updates) (Proprietary, enabled, Not in use)
xorg:nvidia_331 - NVIDIA accelerated graphics driver (Proprietary, Disabled, Not in use)
xorg:nvidia_331_updates - NVIDIA accelerated graphics driver (post-release updates) (Proprietary, Disabled, Not in use)

```

so I enable the 331, and everything was okay