Starts OK but after a short time it crashes with a scrambled screen
The heat will effect your Laptop, on the table no air can circulate. You need to purchase a cooling pad that has extra fans to aid with the cooling of the Main Board. A cheap alternative is to place the laptop on top of a dish and in the dish place an Ice block.
Use the cooling fan all year round. Once the Laptop crashed due to overheating, the damage is done.