Barmoor's Kid Sister
Try running Disc Utility and Verify Permissions. That may well get rid of a lot of the crud lying in the background.
Regarding the problem with Web pages, I had a problem with mine when it was better watching paint dry than waiting for a page to come up. One answer from the Apple Support Communities pages was to reset the Router back to the Factory settings. The comment being that "Some people just reset their at the start of their "work from home" day because it will fail at some point if they do not."