Is it out of warranty? Do you have the money for a new heatsink, which can be hard to find? I don't recommend it. After taking apart one dead laptop and trying to put it back together, I would leave it alone. I've been building desktops for 20+ years, but laptops have alot of tiny wires and screws that can be lost plus the ribbon connectors on some boards. If your Toshiba is fairly new, you won't gain much by changing the cpu; many aren't available; most venders don't stock them.