Look at what memory you have installed. Control Panel/System/General tab.
Look in SystemAdvanced/Performance Settings to see if Windows is managing. In there you can set a fixed size .. I use 1 1/2 x what I have installed as RAM. Custom size min and max same.
You may need to add extra RAM, but this "may" get you out of trouble for the time being.
You "may" have too many background processes running due to installed software running system tray entries, etc..
You should also check that out.
I'm with VHG. Programs written some time ago are often not designed to cope with the much larger numbers that result from faster processors and bigger memory. So (e.g) the program checks for available memory, receives a result that's much larger than it was designed to store and process, and sees it as a zero.