My computer is snappy when I log in from a fresh reboot. Within a short while, it becomes almost unusably slow depending on what I want to do.
In particular, any Windows-y actions are slow while third party applications are fine.
My machine has pretty good specs and abundant memory (Windows 7 Ent. SP1, Core i7 Q820, 16 GB of RAM).
explorer.exe is almost always pegging one of my CPUs (although, since I have 8, it shows 12% CPU usage in Task Manager). It's important to note that you won't see system-wide 100% CPU usage (unless you have only one processor).
svchost.exe might show hundreds of MB consumed, and occasionally also hogs a CPU
Using explorer to browse between folders takes 2 to 5 seconds or more per folder change. I tried setting the content type as suggested by Google results for "slow folder browsing in Windows 7", but this did not impact performance
Starting Internet Explorer can take 10+ seconds. Initially, the window opens but the menu bar remains undrawn for an additional long period. I have tried disabling all add-ons, of which there were none.
Slow speeds regardless of anti-virus. Computer is clean (take this on faith), and anti-virus has been uninstalled.
Clicking an item in the start menu does not respond instantly. You click an item and think nothing is happening because the start menu just sits there as if you hadn't done anything. Then, 5 to 10 seconds later, the program might open.
Right clicking anything takes too long. I have tried using ShExview to disable most context menu items, but this didn't significantly impact right-click performance.
When particularly bad, Windows explorer windows will simply stop responding for tens of seconds or minutes at a time. No abnormal CPU usage except for explorer chugging along hogging a core.
What could be causing these symptoms and what can I do to fix it?