Checking System Resources
Low system resources can cause both performance problems and system errors. To make sure your computer has sufficient resources to run Windows and your applications:

The Performance tab contains information about your computer's performance status:

Note the System Resources line; it indicates how much system resources are available. This value represents the portion of memory available for use by Windows' graphical user interface (GUI). Each application and open window uses a portion of the available memory. When you exit from applications or close windows, those resources should become available again. However, some applications, especially those that are not Windows 95 or Windows 98 compliant, may not release the resources when through using them. It's also possible that Windows won't release system resources when there's a conflict between an application and one or more of the hardware or software components on your system.

The System Resources value should be at least 60%; if it is less, try exiting from some applications or closing open windows. If the System Resources value does not increase to 60% or more, restart Windows to bring the available resources up to an optimal level.