Can anyone tell me what causes this to happen on my laptop? It's only now and then and I can easily reboot by holding the on/off button for a few seconds and then start Windows normally. I'm actually going to dump it anyway, as there is also a problem with the right-hand side of the keyboard, especially when I hit the ? key and it then highlights some text and deletes it as I hit the next key (never notice the highlight quickly enough), or moves the cursor to some random place. Add to that, the wifi signal often drops close to zero. This is because the aerial which is located in the lid around the screen is loose. So I was told by a Microsoft-trained engineer who by a miracle was based in my neck of the woods in Nakhon Nowhere but has since moved on to pastures new.

It's my second HP, and my last. I've had keyboard problems with two in a row now. Enough.

A couple days ago, it was the same on TV, so maybe cable? It never happened before.

I had a similar issue before.  I'm pretty sure it was cured by removing and reseating the ram.

Connect an external monitor. Then you see if the strange picture is on both screens or only on the internal screen.

If it's only on the internal screen than you know that is the problem (including wires, etc.).

It the picture is the same on the external screen than it's not a screen problem.