Downgraded to xp, heat issue

Hello,
I have been using a hp pavilion dv6000 laptop for a year now. It came with vista installed, and because it was painfully slow, I have downgraded to xp 10 days ago. It works just fine now except one thing: it heats way too much (especially when playing games etc) and the computer shuts itself down. I never had that problem with vista and I let it on for days when I was using vista.

I hope someone can help!