ATI Mobility HD4570 crashes

Hi to all. I am a Sony Vaio owner, with ATI HD4570 since December. Some times (5-6 times until now) the pc crashes (total screen flickering and terrible sound loop), even when i'm playing games or listenig to music or watching a video with media player. The only way to restore my pc is by pressing the power button - heavy shut down.

After searching i found in windows log file an error called atikmdag. I reinstalled windows 7, I disabled the catalyst A.I. and now the atikmdag error appeared in windows log file occasionaly the times that I open or restarting pc. (until now I haven't any crashes)

another Point is that I cannot update my catalyst because Sony does not recognize Ati driver Updates.

So all the above are usual or I should send the pc back to sony?

Sorry for my English, any suggestion will be extremely helpfull.

Your English is fine.

What do you mean when Sony doesn't recognise ATi driver updates? Do you mean you can't install it or you can't find them from Windows Update or Sony? If there haven't been any crashes, then, it should be fine. Otherwise if you really want to, you can get the original ATi Mobility Radeon HD 4570 drivers that were installed with your VAIO notebook here:

http://www.kb.sony.com/selfservice [...] 2094160237

I haven't used Vaio's before, but I would think you should be able to get drivers from AMD's site.

http://support.amd.com/us/gpudownload/Pages/index.aspx

Select your OS and then select "Mobility Radeon", then choose "Mobility radeon HD 4000 series".