I have a Sony with win 7 64-bit and 4 gigs of ram. About a month ago I started to notice my computer running slower. When I checked windows task manager (performance) it was using 3.5 gigs of my memory. I restarted the computer and it went down to 1.5. I have on occasion had to restart twice to get the memory down. I have run virus checks and reg cleaner but it still occurs.