Alright so I have a Dell Latitude E7240, and its battery broke so i use it without a battery by just charging it directly through the power supply. I had Windows 7 before and had to clean up some things so I decided to upgrade it to Windows 8.0, at that point the laptop started working very slow, so I thought i got a bad windows copy, however I found a windows 8.1 copy with all the required components, activation key and all the windows updates and the laptop still runs very slow. I can't hear any fan noise and it stays cold, it doesn't get warm or anything as it used to before and works very slow compared to how it worked before, I think it's due to it not having a battery at all however when I had Windows 7 it had the same circumstances and worked perfectly fine even without battery, could it be any settings from the BIOS that control power management due to it not having a battery or anything particular? I also set the power management to High Performance, and still no changes, I don't hear any noise, it doesn't get warm a single bit, works very slow even if it only has one Chrome page open. I don't really want to buy a new battery just to make it work as I know there should be a setting to tweak as it used to work perfectly fine before. Thanks in advance.