Lubuntu: Sceen looks like in negative all the time

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http://askubuntu.com – I've just installed Lubuntu 12.10 on an old laptop (IBM ThinkPad 600X). However, after booting Lubuntu, everything looks like in negative (eg. colors are inverted, like there's some assistive technology enabled). During installation (using alternative installer), colors were OK. Before installing Lubuntu, I had windows installed, it was showing colors OK as well. So, I believe it's something with Lubuntu. Is there any way I can fix that? Edit: I've just installed Lubuntu 12.04. Everything works fine, so this had to be a 12.10 error. (HowTos)