I bought my Dell Latitude 5540 laptop  last July. It was working absolutely fine. It has 24GB RAM and13th Gen Intel(R) Core(TM) i5-1335U   1.30 GHz. I had its USB type C charger working well until it burned up 3 months later. I bought another Dell charger but and it charged it just fine. However, now whenever I take it off the charger it starts lagging and the video apps lag terribly that the videos don't work well. I've tried everything. I updated the BIOS, I adjusted the power options for best performance plugged in and out. But nothing seems to work. Please HELP.