256MB memory is not good for 16x DVD burning in my opinion. My applications use a lot of memory these days. I have 1GB on this PC right now. Another 1GB on the server where the webpages linked on my signature are also running. More gigabytes on other computers.
Check your Task Manager by pressing Ctrl+Alt+Del if you are running Windows 2000 or XP or 2003 to find out how much memory is being used and how much HDD space is used for caching files. When I am browsing multiple webpages, Internet Explorer alone uses about 100-200MB memory.
Use RAM for various "temp" things. It makes many things faster and cooler. 1GB is what I recommend since two modules of 512MB DDR-SDRAM is reasonably cheap now. For most people, 256MB should be enough for 16x DVD burning.