Can anyone tell me why my laptop keeps on totally crashing?

[Carmenere]

It is totally virus protected, scanned, spyware-proofed, ect yet for some reason it keeps on crashing out to a black screen and when I re-boot it all the info in the drop down menu on my browser is gone. Is it just over-heating? Is it a mechanical problem?

Pleeeease

.

I thought this was due to over-heating but now it is happening within a short time of switching it on
I really need to get this sorted as all other computers in the house are either busy or messed up.

Could be a dodgy power supply. Try running it plugged in but with the battery taken out and see if that improves matters. But I'd also take it as a warning of possible upcoming terminal failure and make sure you are backed up properly.

and can I take it back to pc world and have them fix it do yo think?

I'd ask them to check it out, certainly.