MSMPENG.EXE is using up approx. 100% of my CPU and causing my XP Professional system to bog down or almost stop. Is there a fix? Please Note: I have been using Windows Live OneCare (WLOC) for years. Since Windows Live OneCare Support is ending, I removed WLOC and installed Microsoft Security Essentials. The 100% CPU usage issue existed with WLOC and still exists with Microsoft Security Essentials.1 person got this answerI do too

I discovered what was eating up all of my CPU; a program I have called "Paper Port" (used with my Xerox Scanner-made by 'Nuance'), has 2 programs that "Constantly" keep running and checking for updates. I didn't really see the "Running Files" in "Task Manager," so it was difficult to figure out. In my research, I found a program Microsoft had called ProcessExplorer (procexp.exe). When activated, ProcessExplorer clearly shows (in child like terms), what programs are running and the amount of CPU usage for each. I clicked each running file, hit the Red Check-Mark and "Stopped" both processes. My CPU usage went from 90 to 100% to 5 to 10% depending on what I was doing.The sad upsetting thing about these 2 programs constantly running was the fact that they never gave information on "Updates" to make the program run better or to fix bugs, these files "ONLY" notified you of "New Programs to Purchase!" I forget the exact name of the main file but it was something like, "ISUM.exe" and the other CPU Hog was "Agent.exe."