in case anyone wants to know this.
3 POSSIBLE methods.
1 - use a vbscript to clear entire internet cache, (google for code)
2 - when specifying download location add a random integer to the "save to" location on hard disk, then rename file after download
3- Add a random INT into the URL (more reliable) but mught not work with ALL urls..
e.g take the url for google log
we then add a random PHP style parameter to pass to the server, which will get ignored but fools your browser into thinking its a unique new url and WILL redownload the file: