Help?

[fallingfast;]

Okay, I'm not sure if this it the right place to put it but...

Lately I've been getting this weird thing, like everything stops and my whole computer screen turns this darkish blue colour, and it tells me to shut everything down to protect my data or something like that.
I've got some questions...

1) Does anyone know what this could be/has experienced it before and knows what it is?
2) Is this a virus? I got a pop up earlier, saying that a virus was blocked or something like that but...
3) Does youtube/facebook give you viruses? I go on that a lot so...?
4) How can I get rid of this? I've had it more than two times.

Please reply, and I'm sorry if this isn't the right place to post this.

[Fray <3]

1) Does anyone know what this could be/has experienced it before and knows what it is?
This is a virus, as this has happened on my computer.

2) Is this a virus? I got a pop up earlier, saying that a virus was blocked or something like that but...
Yes, it is a virus.

3) Does youtube/facebook give you viruses? I go on that a lot so...?
Youtube may be the main thing, that is causing this to happen. It may be facebook.. the games some times cause viruses.

4) How can I get rid of this? I've had it more than two times.
You'd have to google, what it is called. There is something I used, to get rid of it. I forgot what it was called.. but like I said, google knows all

Good luck, and I hope it goes away soon.

[fallingfast;]

Thank-you so much! I'll do a scan onto my computer and check. Thanks again <3