For the past 6 months, I've been using a cheap laptop I bought from a friend and it always gets the power from being plugged into the power point since using the battery isn't good enough. Yesterday, I had to do a big video encoding job and it lasted 8 hours (I just let it do it's job and I went to work while it was running) then I turned it off. The next day, I decided to move the laptop to the living room and tried to turn it on. Nothing. Panicking, I decided to plug it into a power point and it worked. After doing as few work on it, I decided to move the laptop to my room while it was still on. Nothing wrong. I've been doing it several times but this time, when I removed it from the power point, it just switched itself off. Is this something to do with the battery and I should order a replacement and if so, how do I prevent it happening again?