Managed to get this damn machine working with debian quite long time. Even managed to get network working (ethernet).
'1) Suddently again, while editing a picture using SO 5.1 the power went off. 2) While trying to boot again it gave the normal messages like 'not cleanly unmounted, check forced' etc. Then again sudden shut-off. This happened three times while trying to boot. The fourth time worked and it managed to check the partitions... Now it has been working again. 3) There isn't any overclocked CPU or anything like that. As far as I know this thing has never happened with this machine with windows. I put most bios settings as defaults. APM disabled as well as all shadow ram settings disabled. Power-button override disabled. Still don't know, where the problem is. Just waiting for the next shut-off... In my opinion it (shit) happens, when there is some large swapping going on. The machine has got atx-boxand automatic shut-off of the power, when shutting down windows.