they are not deleted, you have trouble with your browser set up
do this
IE7
=======
Over time IE7 seems to set its own (or programs do) tick boxes in the advance tab.
In IE7 Tools >Internet Options >Advance Tab
Click Restore advance settings defaults button.
Then scroll the listings down to near the bottom and:
Tick empty temp files when browser closes (this empties the cache, which if not empty, will stop you from going online).
Bullet disable phishing filter (optional. Leave it on if you want that type of protection, usually for financial data like internet banking)
Delete Browser History, cookies, add ons, the whole lot regularly.
Close the browser to set the settings.
Flash9e problems
=================
In XP, go to add remove programs and uninstall macromedia shockwave and also uninstall adobe flash, and adobe shockwave.
Using Explorer, go to c: windows/system32/macromed and find the uninstall active x file in one of the folders, and run it.
Then delete the contents of macromed folder. If a particular file will not delete, right click >properties and un-tick the read only attribute. If it still will not delete , boot in safe mode and delete it, them boot normally.
Then google adobe shockwave and install it.
Then google adobe flash and install it. You will have to allow active x to help install which is ok.