Have a Gateway, running XP Media with 3G harddrive and 1G memory. If I'm away from the computer for several hours, I will not be able to open any of the desktop programs and I'm assuming any from the Start button as well, unless I do a complete shutdown, wait a while and then turn the computer on. If I have my screen saver on (Webshots with 10 photos) it will shut down and not come back on the manual restart. I used to get Out of Memory notices, but changed my page file, by your instructions to 1500 as Minimum and Maximum.
I also changed many of the resident programs on the taskbar to Always show, like Volume and Wireless connection and put Never show on others, but after clicking ok, I still have the same ones as before and not the ones I indicated.
Don't know if this is all connected or not.