I have a pentium II 266 overclocked @300-tried for 333 but programs became unstable-I'm confused if whether I should leave the case cover on or off. I find taking it off reduces some heat off my motherboard, but attracted some dust particles on it and a decent amount on the fans of my Card Cooler for my videocard. On the otherhand, leaving the case cover on inhibited the collection of dust but increased the temp. Furthermore, I read something saying that leaving the case cover on promotes proper airflow because of the design of the case. If anyone has any personal experiences or tips please reply, thanks.