I was going to watch this YouTube video then suddenly my pc turns itself off ... what does this mean D: I remember deleting stuff in my pc yesterday ....

What must I do to fix it D:

Must be just overheat used to hapent to my old pc its np

Try running a virus scan, you might have some malware. Malware Bytes is free antivirus software you can try and download.

What exactly did you delete? If it was an infected file, deleting it most likely won't get rid of the virus. Or you probably deleted some important files that your computer needed to run. It could be a multitude of problems, your computer might have just overheated.

Maybe u deleted something like the plugin to play videos

That happened to me too with my last laptop. The problem stopped after one month or so, then the system suggested to get a new battery.

I don't know what can you do if it's a PC, but it shouldn't be related to the files you deleted unless those were inside the Windows folder.

how would that happen
i can delete the whole browser while its open
and it wouldnt turn off the pc
ill recommend you to install fanspeed
and check cpu/motherboard heat this is the main problem
if its over heated
get a good heatsink and fan
if you have a good one
the main reason could be that the heatsink isnt touching the cpu
-----
did you over clock your cpu in the past dayz?

Like the others have said, it could've overheated. Computers turn themselves off when it gets too intense to prevent permanent damage.
But yet again it could be other things, firsts things first though.
Open up your computer and give your fan a clean, make sure nothing is blocking the part of the computer where air comes in and the part near the fan where air is pushed out, if either side is blocked, then the air inside will get hotter and hotter without leaving and cause overheating.

If it helps, don't bother putting the cover back on after you open up the computer, it's not needed and it easier for air to get into the case.

I wouldn't be too worried though, if it's just the odd one time thing, if it happens again after you've done what we've said I'd come back and say so : )

ah there you go. i just put a fan near my pc so it wont overheat. thanks guys