1 Try and fix it and destroy it, thereby having to buy a new computer.
2 Wait till it self-destructs on it's own by being filled to it's capacity with useless tripe, thereby having to buy a new computer.
3 Overloaded with so many viruses that it won't even turn on anymore, thereby having to buy a new computer.
See my conundrum?
Don't overly worry about cookies... People get worked up about them, but most are benign, like FR's cookie and those of other sites where you've set up an account and want to remain logged in rather than log in at each visit. If you delete those cookies, you'll have to remember your login.
It can save you some space to clean up temp internet files and cookies from time to time, you can most easily do this by clicking "My computer - Right click your C drive and select "Properties" - click "Disk Cleanup" - and letting your computer clean up temporary internet files, your recycle bin, and cached web pages all at once.
If you like, I *think* I can walk you through using Ccleaner-- the wife just got a new Dell toy, so I may be offline a while, but let me know if you would like my recommendations for what to check in the boxes.
The main thing is to not delete your cookies unless you have all the logon info you use for various sites written down, because you would then have to do that all over again. Spyware removers like Lavasoft's Ad-Aware or MSantispyware ( I prefer the latter ) should clean out the bad cookies anyway.