Some cookies actually speed up browsing, contain useful user information (like the local store near you), or hold passwords, etc. These are the GOOD cookies.
Other cookies, the BAD ones, are used to report information about your browsing habits, etc., without your prior consent. A good spyware application will generally be able to decide which cookies are harmful and allow you to delete them(AdAware SE Personal, for example); your browser settings should always be set so you are asked whether you wish to accept them or not.
Cookies should not noticeably slow down your computer's operating speed. More common causes are:
1. Running too many unneeded programs or applications on start up; each of these takes some CPU usage, which, if added up, could slow down your computer.
2. Not doing clean up mainteance on your hard drive. Failure to delete old programs, clear temporary internet files, run scandisk and then defragment your HD can cause a slowdown.
3. Spyware or other malware residing in your computer.
Edited by jgweed, 08 September 2004 - 06:32 PM.