Computer is randomly freezing AND shutting down randomly?

Alright first the freezing part randomly out of the blue my computer will freeze i won't be able to move my mouse the time won't continue and I can't ctrl alt delete. My computer also will randomly shut down as in I'll be doing something and it will just turn off and I'll have to turn it back on no blue screen or anything. I have already did a full av scan and I have cleaned my registry with ccleaner I have tried countless things but none have worked I have windows 7 professional my computer is a lenovo thinkpad edge (laptop) 8g of ram and yeah what could be wrong? Note shutting down normally happens when doing something pc intensive and freezing will occur randomly

Although the problem can be caused by hardware overheating is a common cause like you describe.
overheating can be caused by dust, etc clogging up the vents.
You can Google "how to clean a laptop" and you will find videos and instructions for cleaning.
Even if the problem is not fixed you will have eliminated one likely cause.

Could be your hard drive.
Turn it off, then back on use f8 to go into safe mode, than to a full scan

Low on RAM