Please help

I have a 2009 mac pro running snow leopard. When I open iCal or safari programs, the windows do not open even though I can see that the program is running in menu bar. Rest all is running fine. I called the apple care two days ago but they couldn't solve the issue and have referred the problem to apple engineers (have not heard back from them yet). I'll appreciate if any of you mac experts can help solving the problem.

Thanks
Krishna