Ouch, you have lost 2 ATI 9200 video cards on a HPZT300 series, eh? Make sure you go to X1000forums.com (site for HPZT3000, Compaq X1000, and HPnx7000 business)to post this and do a search for this topic already.
Ken here from Ifixit has posted he has done some repairs for video cards and there are some people who have had to replace them at X1000forums.com but I was not aware of 2 in 13 months.
I do not use my Compaq X1000 heavily and I don't play games on it (I mostly use it for wi-fi internet access) so I probably don't strain the video card enough to do this.
If you are using a coolpad perhaps you are an gamer and are pushing the video card as the fan does not run much at all on this model unless you are using the hard drive or optical drives heavily.
I use a Targus Podium Coolpad (29.99 retail -- sometimes a rebate -- see Targus.com) to elevate the rear and give a nice tilt to the keyboard. However, this does not draw any power like the USB coolpads with fans you are referring to.
Pavilion zt3010us, 13 months old, second VGA card..
I've been doing some reading lately about what hazards to keep your notebook away from and there are several. One in particular is the "magnetic field".
Now the articles don't say how strong a field could be harmful over a period of time but I wonder about the magnetic field being produced by a laptop cooling pad with 4 fans.
I recently (like yesterday) lost my VGA card (2nd in a year) for no apparent reason....again,
Anyone else have a cool pad under their laptop?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic