Verified answer

It all depends on how you use your computer, if you just download and surf the net use CCleaner and Defrag once a week. Also use the 'Analyze' function it'll tell you whether or not you need to Defrag :].

The easiest way to handle your kind of situation is to set an automatic defragger to run in real time background mode. Among the defragmenters I have tried, I have found Diskeeper to be the most efficient. Its also very easy to use as it can be set to defrag automatically in the background (which means you can use your PC as usual even while it runs), has a nice GUI, defrags under low free space and defrags system files. For Vista, it has a VSS defrag option that prevents unnecessary shadow copy activity.

Try the 30 day trial if you wish

http://www.diskeeper.com/defrag.aspx

If you do a lot of downloading and deleting, chances are that fragmentation builds up quite rapidly on your filesystem, so defrag regularly.

Check out an automatic defragmenter called Diskeeper 2009. It's the best defragger for windows, and automatically monitors for file fragmentation and defrags all drives in the background automatically as required.

http://www.diskeeper.com/

You won't have to worry about manual defrags for any of your drives then.