I have developed a WPF application which runs for months without any errors shown. Suddenly, one day, it happened to eat 50% CPU and remained non-responsive. The machine has not updated any patches for .net framework / windows operating system. That is, external environment has no changes, but the application suddenly hangs. What I have seen so far is that ram usage, number of threads and I/O counts remain unchanged after it eats up 50% CPU. What would be the cause?
Thanks.
p.s. the application (built for .net 3.5) runs on microsoft .net framework 4 and microsoft windows 7, with microsoft SQL server compact edition 3.5 sp2 and WPF framework.