I have had this laptop for a long time (five years at least) and it hasn't had the best treatment over the years.

But over the last few months, it has been randomly completely shutting down, no blue screening, no steady shutdown, just black screen, then BIOS.

I think it might be happening as I do a save, but cant be sure, but recently it has been getting very annoying.

I did initially think it was an overheating issue, but the speed that it comes back online is staggeringly fast for it to have cooled down sufficiently. plus it has got incredibly hot before with no issue (since its been doing this).

Does anyone know what might be going on?

Dell Inspiron 640m, running Windows 7.