Everyday I've been getting this annoying "out of memory" error from XP. Sometimes you know its happening when you open a open and it wont load, open explorer and the menus are empty, clicking someone's name on YM and it wont open any IM window, photoshop crashing, etc. But why is it happening? I still have over 500b of physical memory available.

Googled and found a page in Microsoft's KB. Just sharing this in case anyone else is having the same problem. B)