text: why do i sometimes not get any power to my laptop when it is plugged in? i have a live power source and i can unplug everything then replug and sometimes the power will come back.  my laptop is 3yr compaq pesario 2570. not sure but try unplugging it, taking the battery out and try to turn it on. i know it sounds dumb but some laptops it kind of resets like that, not that you will lose any info. also do a search on your pc and see if there is some program to recalibrate your battery, you might just have a bad power cable that is not charging the battery properly.