Laptop will not power on with battery connected.
I got it from a friend after helping them build their PC. It was running extremely slow. I reinstalled windows, which somewhat improved the performance. I followed up by opening the laptop and thoroughly dusting it, and reapplying thermal paste to the CPU and GPU, as the old paste dried solid.
While it was open I decided to exchange the 1TB 5400RPM hard drive for a 1TB SSD, to further improve performance. When installing windows to the new drive the laptop died. I accidentally unplugged the cord. I knew the battery was dying, but it took less than 30 minutes to discharge so I ordered a replacement. Now the laptop will no longer boot while either battery is connected, but will boot while the battery is disconnected and running from wall power.