I have a ATI 2400HD Display Card with twin output. I have connected with 32" Samsung LCD Monitor. Mainly i use DVI for primary output and no second monitor output. Sometimes it change to very low resolution and error msg show it "reinstall ATI display driver". Then I restart Computer it work noraml again. May I ask what cause? And What can i do to prevent or fix the problem? Thanks.
Try to keep your graphics card driver up to date: AFAIK, today Catalyst 9.3 will be released, so stay tune. If this won't help, try to install your monitor driver (maybe you'll need to download it from Internet). Then, if this won't help too, try to check your DVI connection - the problem could be in DVI connector of graphics card (so try other one), in DVI cable itself (do you have a firm one?), or even in graphic card! I'd like to suggest you to test your graphics card with another monitor, or (if it's possible) another graphics card with this monitor.
It could definitely be a problem with compatibility. Hardware needs to be upgraded, just like software does, occassionally. I'd check Samsung's website for a monitor driver upgrade, too. That may help in the long run.