If you're using IE (microsoft), then you have to manually empty your cache once in a while. Don't ask me why, by the Gatesian philosophy is to leave all kinds of temporary files cluttering up the hard-drive, and messing with allocation tables.

Pull down the Tools menu, and select Internet Options. On the General tab, under Temporary Internet Files, select Delete Files. A smaller window will open, and tick the box to delete local files. Select OK. Be prepared to wait a while if you haven't done this before. Over half of the entire file content on my hard drive was cleared off, the first time I did that. 17 GB of temporary madness. My caches worked fine after that.

Lar