Low resource problem
A 'low resource problem' occurs when Windows is running too many programs at the same time, or has been running multiple programs (not necessarily at the same time) since the last time the computer was rebooted.

When Windows starts up, it allocates a certain amount of memory (called 'resources') to specific functions, such as screen display and program memory. As programs launch, they grab onto these resources. So, running too many programs at once may give you a 'low resource problem' and closing one or more programs should resolve it.

Sometimes, resources remain locked up even after you've quit some programs. The computer will run slowly, possibly even crashing, until you reboot (re-start) the computer. Rebooting releases all resources. (see Defrag and Boot (or Reboot))