I have a lenovo n22 laptop. I am posting this message on it. I was watching i a youtube video when I realized that the ac/dc adapter was unplugged, when I plugged it back in, my laptop made a errrrrrrrr noise and then froze, I turned it back off and turned it back on, 40% of the battery had been drai ned. But now, I can't charge it, this is the only charger I have. When I pl ug my power cord in, the screen will flash black for about 1/5 of a second. I checked the power cable and it was still giving me current. I don't know if the adapter has been fried and it is trying to put ac power into my lap top or it has just fried the power component in my pc. I need a way to see if the adapter has been fried or not I need a way to test for alternating c urrent without a meter. I have 18% left and I am currently backing up every thing. Urgency is needed. I have no other way at my house to a computer.