>>>1.) How do I "defrag"?

Click on "My Computer"
Right click on the Drive you want to defrag.
Select "Properties"
Select "Tools"

>>>2.) How do I remove "cookies"?

Click on "Start"
Click on "Control Panel"
Click on "Internet Options"

Please note that you generally don't want to delete all cookies but only the "bad" ones. Get a freeware program called Ad-Aware SE found here:

http://www.lavasoftusa.com/software/adaware/

It will remove all spyware, insects, parasites, and other such nonsense from your computer.

Good luck.