Several times I was running Helena KDE on my laptop with energy from battery. When, after that, I tried to leave the system (either hibernation or shutdown), the screen started blinking (showing strange bands and colours similar to interferences in old TV) and the system became unresponsive: neither ctrl+backspace, nor ctrl+alt+supr, nor Alt+SysReq+REISUB, worked at all... I had to press shutdown button
Any idea? I have searched on the forum but I found no reference to such problem with Helena KDE.
Thanks in advance.