Pc only with power supply?

To
1

My laptop only works with a power adapter even when the battery is full. (Xp)

As soon as I unplug this he goes out.

Why is that?

Ga

I see that XP is installed on the laptop. This means that the laptop has been around for a few years. Lithium-ion batteries tend to be defective despite the battery level being full. Often dependent on age. That is probably the case here. So the battery is defective.