I had this happen a while back. My windoze 7 machine with 12 gb of ram would run out of memory and eventually blue screen after about two weeks plus. Win XP and NT2000 in about a week would BSod as well. Drove me nuts. Found out in resource monitor that killing java.exe would allow the machine modified mem usage not to expand. So java was leaking, and though it was not using an an unusually high amount of ram it was also not letting go of what it had used making it modified. Solved by going to Sun Microsystems site and using their utility to uninstall previous versions of java and installing the newest one. Hope this helps.