You now mention that its a laptop. That makes a huge difference.
Do you have the laptop plugged into the AC wall outlet, or are you running from battery power? If its the last, then there's most likely a powersaving mode that is putting everything back.
You should also try to update your drivers. Do note though, that NVidia isn't as good with 2D graphics, as ATI is. I don't know what your previous computer had when it ran XP, but if it was ATI, then that'll make a huge difference as well.