> Handles: Your oldest enemy
If your computer is starting to run slowly, before rebooting it try checking for how many handles a given program is using.
To do this, bring up task manager (ctrl-shift-tab), go to Details and then add the Handles column. Anything over 10,000 handles should give you pause. The more handles a program uses, the slower it will make your PC no matter how much memory or how fast your CPU is.