It's probably your internet cache not internet history. When you access a web site some content is stored locally so that when you hit "back" the page doesn't all have to be reloaded. Google "Temporary Internet Files".
For WinXP the location of this folder is something like..
C:\Documents and Settings<username>\Local Settings\Temporary Internet Files\
That folder might be hidden and I think XP puts up a warning if you decide to unhide system folders.
More info here on how to empty the cache..
http://support.microsoft.com/kb/260897