Win32 application windows eventually stop painting on Windows 7

Question

I have a large, complex application written in C++ (no MFC or .NET). The client that uses the software most aggressively will, within an hour or so of starting it, get to a

Answer 1

I'd bet that the application is leaking GDI objects, and when the GDI dedicated space for this process is exhausted, it can no longer paint itself.

You can check if this is the case by adding to the Windows Task Manager (or any other process manager such as Process Monitor) the column GDI Objects and see if this number grows unbounded with time.