Hard drive indicator solid, seemingly large activity from System process (PID 4)
OK, I assume you didn't deliberately change anything. If you did, start checking the drivers for your latest hardware before doing anything else. Symptoms: Stable Windows 7 x64 system suddenly has HDD indicator light on solid (or nearly solid). Happened suddenly without warning, re-occurs within a few minutes after booting. PC will freeze for at least several seconds at a time. CPU activity is high. Task Manager is slow, hangs frequently and tells you nothing useful. Process Explorer seems to show System process (PID 4) taking lots of CPU, but no other details - no real indication which process is actually hogging your hard drive. Turning off antivirus doesn't help. Acrobat may complain about a "serious error" when started and/or freeze up. Inability to use Disk Management tool. Shutdown takes tens of minutes, if it happens at all; might freeze on "Logging off" or "Shutting down". Cause: Something probably ...