Some limitations on Visual Basic, and the applications you create with it, are imposed by Microsoft Windows. These limitations may change when you install a different version of Microsoft Windows.
Every open window uses some system resources (data areas used by Microsoft Windows). If you run out of system resources, the run-time error "Windows is running low on available resources" occurs. You can check the percentage of system resources remaining by choosing About from the Help menu in the Program Manager or File Manager in Windows NT 3.51, or, in Windows 95 and Windows NT 4.0, by choosing About in the Windows Explorer Help menu. Applications can also call the Windows API GetFreeSystemResources to reclaim system resources, close windows (such as open forms and Code windows, as well as windows in other applications), and exit running applications.