Thanks for your tip. I was also thinking about trying Debian stable.
There is another option, which would be to change the video card of the computer.
But I don't have much time. This is my parents' in law computer not mine, and when I go to visit them with my wife, I don't want to stay the whole day in their office doing computer maintenance. So I decided to use W7, which was already installed in their computer.
Yes, video cards and hardware drivers generally is the difficult area.
I was posting my suggestion for others in the same boat. I detect a 'blind spot' sometimes in some replies to discussions like this about the fact that the operating system is GNU/Linux, and a distribution is just that, a convenient collection of packages and an update system/policy. If someone else finds (say) Ubuntu 10.04 works really well on their hardware, they are likely (but not certain) to find that CentOS 6 will do just as well.
I use a recycled Thinkpad with Intel graphics, so any major Linux distro is a half hour install, with most things working out of the box. Debian is strict about proprietary binary blobs, and so needs a wired connection to install and add the firmware appropriate to the wifi card. CentOS I recollect 'just worked'.
My reason for using CentOS on the laptop is that there is a definite update life published. Debian release their new version 'when it is ready' and the current stable then drops to old-stable with a year of updates. This approach admirable, but I find it easier to slap CentOS on and forget about it until the laptop dies! Sort of the XP of the Linux world.