Windows (and all other modern OS's) tries to find a use for all of your RAM (free RAM is wasted RAM). Most of what you are seeing is simply a cache of the most commonly and recently accessed data on your system (it learns by watching your activities). Memory used by the cache will be given up to applications on an as needed basis. There's nothing to be concerned about here, just let the OS manage its memory (it does a much better job than you could ever do manually). And whatever you do, NEVER turn the page file off. Windows requires at least a minimal paging file.