After 5 or 10 minutes of playing a game (Morrowind, Oasis), the computer
crashes when on AC power. It doesn't crash when on battery. It' s a laptop.
It strongly looks like the laptop is overheating, performance ( and
temperature) is usually decreased on battery. Most laptops are not
good games machine not only because they are often underpowered but
mostly because their cooling is rather inadequate for demanding
applications.
Try to lower the game settings (resolution etc...), make sure the
laptop's own cooling system is correct (no fan output blocked, sit it
on a cooling pad...)
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All the best!
Katy Pluta