I have a strange problem. When the battery reaches about 20% and I try to charge it but it doesn't charges. what I did is to turn off the laptop and try again. at this point I must wait until the battery reaches 20% otherwise If I'll turn on the laptop, the battery will stop to be charged. in shortly: I can't carge the computer and turn it on at the same time when it's below 20%. How can I solve the problem please? Thanks for answering!