Where to start?
Just like the closet, first get rid of excess baggage.

First in My Documents.
The ideal is to not have one file loose in Documents.
All files should be in folders.

We know that we create a folder give it a name and put the
relating files into the folder. This is called file management.

If this seems to be an overwhelming task because there are too many files to deal with,I would suggest you look at your files and then decide the subject titles and make the folders.

This at least gives you a start. When you are now saving a file in the future, make sure you save it to the corresponding folder.  If there is no folder for the topic of the file create the folder and put the file in it. This makes sure that the loose files are not growing.

Whenever you have an extra 10 or 15 minutes start to deal with the files already in Documents putting them in their corresponding folders. Little by little you will get the upper hand of organizing Documents and it will never get overwhelming again.

This method I would also apply to Favorites. Once again an area that can get out of hand.
Same method, create initially all the folder topics you think applicable so you have them to use immediately then slowly organize the remaining favourites.  (by right clicking on a favourite you can sort all of them alphabetically, this is a help.)

Emails:
Emails need to be cleaned out as well.

Rule of thumb there should only be emails in the inbox that you have just received and are in the process of answering.
All the other emails should either be deleted, or saved in personal folders you have created.

It goes without saying that the deleted items folder should be kept emptied regularly.
(have seen over 500 emails in some deleted Items folders)

Desk Top
Another area that as when you are downloading a program. I find it easier to find it on the desktop and then install it from there. I create a setup folder on the desktop and drag all the setups into it. if I need to reinstall a program the setup is right there in the folder.

Some people get into the habit of saving files to their desktop and this is when it becomes very cluttered. I have a client whose desktop is a jumble of files and folders and no matter how often I mention the fact that he is losing so much time looking for what he wants he still continues in the same way. It´s fine to use the desktop for a temporary place to save a file but when you have used it then resaved it to your documents in one of those lovely folders you have made as stated above!

My Pictures
Same goes for My Pictures.  A well organized Pictures folder is so important.
It will save you so much wasted time trying to find that picture of Aunt Harriet, B´day.

Also to delete all pics not needed or duplicated. Photos, music and videos take up a lot of space on the hard drive. This is why computers now have mega space hard drives.

Another Space saver is clean out Programs that are not being used.
Silly to have a program taking up a lot of space and which will never be used.

Well now that we have a clean organized closet (and we all know how wonderful that feels)
we can concentrate on the other areas of cleaning.

I recommend a program called CCleaner. just google ccleaner in the search box. Download and install it. It is free.

It is one of the better free maintenance programs out there, highly applauded by the techies.

It will clean out all the superfluous files that are not needed in the computer,
temp. internet files, temp files, cookies, history, etc.
and clean the registry of any problems.

Last but not least, Defrag.
The link below is for a deep defrag program. It will take a couple of hours to do so you can set it up to run during the night. Smart Defrag, speeds up the computer  by defragmenting those slow files in the background automatically and quietly.  Best of all, it is completely free. Smart Defrag has received very positive reviews from publications such as CNET, Chip and PC World. A smart tool to maintain your system performance, speed and stability for no cost at all! You can download and use it for free at http://www.iobit.com/iobitsmartdefrag.html

Well we have done quite a lot up to now.

From here though we should give some thought to our security programs.
Make sure all antivirus, antispyware programs are up to date.  Then run the internal scans that
they provide.

Make sure the Microsoft Updates are installed and all updates on Firefox (Firefox 3.6.3) and Internet Explore 8 have been checked.