Was running perfectly yesterday.
last night I was working and closed it. I then went to bed and this morning I went to power it on and the screen remained black.
I powered it down and about an hour later I powered it on and I had to select "open windows normally" or something like that.
It went to windows and I went online when suddenly my mouse stopped working and the screen froze.
After another 20 or so seconds it shut down.

I tried again and the same thing happened.

Any help would be great.

Thanks in advance

I'd guess overheating.
Clear all the vents & the heatsink/fans.