Problem viewing on two screens since reinstalling XP

I had a problem with my Acer Aspire One ZG5 recently, where it kept shutting down for no reason. When I switched it back on it would display the message ‘Windows has recovered from a serious error’.

I ran a virus checker and adaware but it still kept occurring so I decided to format it and install XP from scratch via a copy of XP that I have a licence key for, as the Acer Netbook didn’t come with installation disks.

After reinstalling Windows, I downloaded the drivers for the netbook from the Acer website and all seemed to be OK and the shutting down problem is now fixed. However, I now have a problem with viewing video files on both the netbook and an additional screen at the same time. I have never had a problem with this before and used my netbook a lot to view films that I download via a VGA cable and an audio cable connected to my Sony Bravia TV.

I would press Fn and F5 and then select the icon for both screens and the film would display perfectly on the netbook and the TV screen. Since the reinstall of XP, if I select the option for both screens, then the film freezes and sometimes audio can be heard but with a freezing and blocking picture. If I select just the TV screen or just the netbook screen via Fn and F5 the film is perfect. To check it wasn’t a problem with the TV, I tested it on my desktop PC screen via the VGA cable and exactly the same freezing happens as with the TV.

Any advice would be very welcome.