Dude, I got the exact same problem. 
maybe you can write some details of your computer, what is your normal (idle) temperature, maybe your ram, graphic card, CPU, version of Windows,
that can help us solve this problem...
I have installed new updates for my computer, i found some new ones in Windows Update and those were some security updates, silicon images pseudo processor device, aktualization of Windows Vista and windows mail update.
Hmmm...This can be caused by: Older drivers, damaged drivers, dust(it makes your computer temp higher) or maybe even something else, ill try to check some more stuff, and gildor please stay tuned for this topic, i think you and of course i want the problem to be gone, fixed, well ill search in google youtube reinstall Direct x 10 and hope this shows some effect.
Juraj
UPDATEI did some searching in google and we are not alone to have these problems, yes, it is your graphic but not card but DRIVERS! I stepped over this site here
http://blog.stevex.net/index.php/2007/03/01/display-driver-stopped-responding-and-has-recovered/ here is the comment (if you fail to find it):
hi, all
to fix the problem you are all getting, just simply go to the folder:
c:\nvidia\winvista\driver version number\
then open setup, and install the drivers it should then work, make sure it gets admin too.
If you still need help for any problems related to vista drop me an email at
[email protected]if that didn’t appear it is jad at webplanethosting dot net
you can trust me as i beta tested vista for about 7 years

still remember good old longhorn :P
Thanks
Jad
or this might help i think:
I have had the same problem with 101.41 & 100.65, but it take a while for the problem to occur. Strangely, I thought one of the main differences was the separation of the driver from the kernel. Somehow it appears it is not fully separated, even tho it’s one of MS’s big selling points on the OS. I am not going to be able to test a solution I found on the web, but possibly it could help you guys out:
I have found and fixed the problem today. This is what appears to happen.
during the installation of the most current drivers 100.65 Vista, an OLD file
nvlddmkm.sys is copied into windows/system32/drivers and not the current one
in the install. As a result the new drivers are attempting to access a file
dated 11/2006 instead of 2/2007 ver 7.15.11.0065 which is in the newest WHQL
driver ver 100.65 vista 32.
Fix: Go to windows/system32/drivers and rename nvlddmkm.sys to
nvlddmkm.sys.old. Go to the nvidia directory and find the file nvlddmkm.sy_
and copy it to windows/system32. Using the cmd window (DOS box) type
EXPAND.EXE nvlddmkm.sy_ nvlddmkm.sys. When the expansion is complete, copy
the new nvlddmkm.sys to windows/system32/drivers and restart the computer.
Your computer should now work properly.
You will notice that any uninstall and reinstall of nvidia drivers will not
remove the old nvlddmkm.sys file and will not overwrite it with the newer
version. You have to do it manually. I do not know why this happens but who
cares as long it is fixed.
If you have this problem then check the link these comments!
I hope i helped you Gildor and myself.
IN YOUR FACE newarvuti !!!ANOTHER UPDATE!You can also solve this by downgrading your direct x to 9.