I was having this problem with mine, and went to [link=http://AnswersThatWork.com]AnswersThatWork.com[/link]. This site is great. It gives you description of all the programs running in the backgrounds and ones you can get rid of. I even went ahead and spent $20 on their software to help eliminate these programs. Funny, one of the problems was my new soundblaster card. Ones of the programs that runs in the background is a huge memory hog. I eleminated that and about 10 others and everything runs great now. And my system didn't loose anything either.
I just wanted to pass this on, because I know this is a problem for lots of people running simulators. My main problem use to be in multi player, but it's gone now . Hope this helps everyone

Jamie


ps. I didnt mean to sound like a commercial, but this site and the program is great. They do have a freeware version, but i figured the $20 bucks was well worth it for the extra features!!!