If the selected page comes up rapidly, your computer has loaded the page you last looked at, which is stored in the 'Temporary Internet Files' folder in windows.
If you get the rapid load, hit the 'Refresh' Button and the latest version of the page will be downloaded.
Whether you alter the settings to get the machine to check for the latest version or us the refresh button (as I do) is up to you - the reason I use Refresh is that it can be irritating to download a page each time if you are doing a lot of surfing and moving between a number of sites, say for comparison purposes (like checking specifications of equipment, prices, etc).
It took me a while to figue this one out, too.