Curious. I've never encountered this kind of problem and never heard of it. Does it occur always? when running any application? or only when running one specific? What does this application do? Win 2k professional are the only officially supported system for S60 SDKs, so I guess the problem shouldn't be there. But you can have for example faulty memory chip, or something similar.... I remember having similar problem when running some Linux distribution and changing memory helped me..:-)