Windows XP virtual memory low

Hello there techyv,
Just asking if this error message of windows can be fix? It keeps on showing and I keep on closing all the windows that I have and application. It seems it is stuck. It doesn’t want to close up this pop up even I don’t have any application that is open anymore, unless I reboot, then everything will be normal again.
What is the problem? My pc, my memory or is it a virus?

