System Resources issues

I am running WinME on a P3, 600E Mhz, 128mb machine and it seems that my system resources go from 60-70’s down to the teens and single digits at some point. Programs i have open are MS Outlook 2000 and AOL’s Instant messenger. Another program that acesses the internet is a Program called Weatherbug. Would upgrading memory work to fix this problem. Looking for help… thanks in advance