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What should I do when Ubuntu freezes?
Since I installed Ubuntu 12.04 it keeps on freezing. It happens on different PCs and I don't think it's a memory problem. For example, I recently got a laptoptop with 8Gb of RAM and I got the problem there as well. The only solution is unplugging the machine or pressing +REISUB (I found this magic spell in a related thread).
The problem seems to be triggered by a task switch, e.g. when I press , which moves guake to the background or into the forground or when I press , which switches the current gui task.
I am suspecting guake, chrome, or evince are possible causes of the problem. Having said that, I disabled guake on the laptop and I got the prblem once since then.
I just reinstalled 12.10 and I had 3 freezes in 10 minutes. I wasn't doing anything special. The only thing I was doing was running chrome and gimp.
BTW 12.10 also causes other problems, like not properly showing the menu bar at the top of the window. When I'm running chrome and gimp, the pulldown menus don't show properly. For example, they may have broad diagonal lines with awkward colours such as yellow and blue.
The following is an example of another problem with the file menu:

Any help would be greatly appreciated.