Is There An Easy Way To Free Up Memory After Closing An Application?

I currently am using a mediocre laptop with 98SE and 1 gig ram. I seem to have many applications open a any given time. And any single search through an application, this may involve opening page after page to research a repair only to endup with a pdf file. This eats up mass ram and causes delays which drives me nuts. But even if I close everything up the usage remains high until I close my Internet browser (IE or FireFox) as seen on the graph in the windows Task Manager. If I am not watching this level, then I get the error message that my computer is reconfiguring the memory. At this point I will likely find the computer may freeze or get kicked off, making me start over. Do I have to approach this cache problem with re-adjusting the computer's memory allocation, or how each application is set up, or, hopefully, is there some setting in 98SE or add-on that will shut off all cookies or residual memory usage as that page is closed?