You can put a couple of lines in your autoexec.bat.
Let's suppose your Cookies folder is C:\Windows\Cookies, and your TIF folder is C:\Windows\Temporary Internet Files.
Then do this:
Go to Start/run and type notepad /autoexec.bat (there's a space after 'Notepad'!)
Your Autoexec.bat will now open in Notepad.
Insert the following lines just before the last one:
@Echo Off
Smartdrv
Deltree /Y C:\Windows\Tempor~1\*.* > Nul
Deltree /Y C:\Windows\Cookies\*.* > Nul
Save in 'File'
Now every time you start Windows these folders will be thorougly emptied.
If the path to the two folders is different on your system, it has to be adapted in the batch file.
Good luck,