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ok
but anyway I've already opened it so it's too late everything seems normal on the surface of course

Yes, I've already checked, but it's written correctly
oh yes, and at the beginning, it says input signal.

so it's a HP desktop and yes, it is still under warranty

I don't really know, I was away for two weeks, I came back yesterday. How can I know? Right now I'm here, but it feels like yesterday.

Laptop? Desktop?
What brand? Model?

Is it still under warranty?
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Ignoring is not a shame in itself, however, taking pleasure in persisting in ignorance is!!!

which means incoming signal....

Has your graphics card not burned out recently?

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Ignoring is not a shame in itself, on the other hand, taking pleasure in persisting in ignorance is!!!

If the connections are good, then there's probably a hardware issue. Don't hesitate to contact customer service; it's better not to delay. They are there for that.

Otherwise, you can also open the case and check the connections, but there is a risk of losing the warranty. Anyway, be sure to read the documentation provided with the PC before opening it.
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Ignoring is not a shame in itself; however, to take pleasure in persisting in ignorance is!!!

If the graphics card seems fine and properly connected... then I think it would be wise to take the machine to after-sales service.
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Ignoring is not a shame in itself; however, choosing to persist in ignorance is!!!