I occasionally get 100% CPU while playing an MMORPG (Maplestory), and only while playing that game, but when looking at Task Manager, the culprit is Explorer.exe. I tried killing it, and waited, now I got 100% on Task Manager, I killed that too and went to Process Explorer, that also maxed out my CPU. The CPU would max out for like 30 seconds at a time then go back down and then start up in 2 minutes, and so on, until I end Maplestory. I've run full scans with Symantec, and Malwarebytes, nothing found. can someone help? Running Vista with SP1 on my Dell Studio 1535, Intel Duo 2.5Ghz, 3Gb RAM. EDIT: I am experiencing the same CPU usage with other games.