jetboy - 9:07 pm on Dec 10, 2009 (gmt 0)

Shut it down. Leave it overnight. Does it still exhibit the problems from cold startup? If so, it's almost certainly overheating. I'd guess that there's no airflow over you graphics chip. Either a dead fan, or clogged airways. These laptops have metal grilles just inside the vents, and they can catch a lot of dust and fluff.

You can clean it yourself, but unless you're comfortable taking the whole thing apart (fascia and keyboard off, unclipping the wires going to the LCD etc.) you may want to leave it to a professional.