Vanette- When I'm running Firefox (which is most of the time) along with AOL and mIRC and often other programs I have no trouble. Firefox doesn't seem to add much to the mix as far as memory (system resources). The resources meter doesn't go up much when I load and use Firefox. As for physical space the program takes up on your computer I'd bet it is far less than IE. If I were you I'd go to Mozilla's Web site and download Firefox -- I doubt if your computer would allow you to download it if there wasn't space to house it. My only warning there would be, once installed, Firefox may tell you that in order to get the full benefit from some Web sites you visit that you need specific plug-ins (such as Adobe Flash) but, again, none of these plug-ins are very huge and you will probably be just fine. Joan In a message dated 10/24/2009 10:34:21 A.M. Eastern Daylight Time, VanetteHobbs@aol.com writes: Hi, everyone, How much memory does Firefox require? My computer is so overloaded and slow now I hesitate to install anything else for fear of making matters worse, but a couple of sites that I go to regularly are telling me they won't be supporting my browser much longer; in fact, one tree on Ancestry says it doesn't now and I have to click, "yes, I want to continue anyway," but I have a hunch things would work quicker there if I had Firefox. Vanette