I know this is becoming boring because I have said it several times - do try and understand that the following actions do not work if you are using Internet Explorer.
Warm or Cold Booting the machine will do nothing
Using the back button is also equally useless
You need to make certain that you clear all cookies and all temporary files before you go fault finding!
Why? Because the files remain on your computer even if you switch it off completely.
You can do this in Internet Explorer by:
Tools >> Internet Options >> Delete Cookies >> Delete Files >> OK.
Double check you have cleared all cookies by:
XP Professional (I think XP Domestic is similar) keeps cookies under Documents & Settings>Owners name>Cookies. This is what is flushed by the Clear Cookies command. It is completely unaffected by re-booting.
Ditto the Temporary Internet Files. To check the veracity of my statement. Clear all the files, then visit a distinctive site that you never normally visit (No not one of those! - I was thinking of the Inland Revenue - what minds you people have!) Switch off your computer and then look at your temporary files again (You can find them in Tools >> Internet Options >> Settings which will then tell you which directory/folder they are in. You will see switching off has no effect on the records of where you visited. (That's how the Police trace what sites you have visited!)
If you don't want the bother of clearing files out and simply want to get things working that moment, don't press the back button or the refresh button all they do is bring up the copy of that page that is is already in your cache.
Hold down the SHIFT key and press REFRESH on the browser bar This is the only way you can force the browser to re-visit the server.
I hope this has cleared up why Switching Off, Pressing Refresh and Using the Back Button don't work in getting you out of most problem situations.
Paul